of crushing in minning industry

the evolution of crushing and grinding: changes in the industry by damian

the evolution of crushing and grinding: changes in the industry by damian

Crushing and grinding processeshave undergone significantchanges over the last 20years. These adjustments have focusedon lowering costs and increasing productionand energy efficiency, mainlydue to the fact that the mining industryhas seen much larger projects and consequentlyhas required substantial crushingequipment.

Today, mining companies want lowercapital costs with fewer pieces of equipmentand higher capacity from each unit,even if the equipment is disposable aftera reasonable service life. This is why thethree stages of crushing, which was thenorm a couple of decades ago, gave wayto the two new stages of crushing.

Operating cost efficiency is another important factor driving change. The globalization of the mining industry andrationalization of equipment vendors hasalso seen technology development anddiffusion on a global scale.Metal prices have fallen in real terms, ores being minedare lower grade with higher throughputsand, at the same time, power and laborcosts have increased significantly.

The uptake ofSemi Autogenous Grinding (SAG) eliminated the need forcrushing plants other than a primarycrusher. The use of pebble milling hasseen resurgence in the use of conecrushers. Crushing plants were dusty,high maintenance and required additionalmanpower to operate.The Mine to Mill concept (looking atthe relationship between blast fragmentationand crushing and comminutionenergy) has changed the way engineerslook at the total project comminution.

High Pressure Grinding Rolls (HPGR)crushers have been adopted and haverenewed the need for secondary crushing,which has taken the place of SAGmills for very hard ores. The energy savingsare an important factor in driving thischange.

The public demand for reduced CO2emissions, sustainability in the mineralindustry and higher energy efficiencyensures the push for the developmentof new technology will continue. Someof these equipment items include:

Jaw crushers are now made fromfabricated steel plate and have increasedsignificantly in size. The lubrication hasbeen improved and the use of rockbreakers above the jaws has improvedoperability through easier removal ofblockages.

The transition from the standardSymons cone crusher to moderncone crushers that use hydraulic hold-down clamping with nitrogen cylindertramp iron relief has seen moderncrushers with much more power andcapacity. The automatic control ofcone crushers has eliminatedbogged crushers and maximizedpower draw and through put.

The largest cone crusher availablewas an 895 kW motor (120 kW 20 yearsago) and the development of a 1 MWcrusher is not too far away. The basicdesign has not changed but finite elementanalysis, improved lubrication andhydraulic clamping have seen significantincreases in throughput for the samemachines.

Two stage crushing is very commonwith some three stage crushing where afine product is required. Liner wear is stillan issue as it relates directly to costs andbowl and mantle change-out times of 24hours are still common. Cone crushers dominate the hard rock crushing market;however, other technologies are beingused on soft rocks. These are crusherssuch as the MMD sizer and impactcrushers.

Autogenous impact crushers of theBarmac type have advantages in energyefficiency and reduction ratios and canhandle abrasive ores such as BandedIron Formation (BIF) in a pebble crushingduty. The breakage mechanism is one ofrock impact against rock, so wear rates ofmetal components are greatly reduced. The Canica crusher uses impacting oreagainst a solid steel anvil to achievebreakage, such as the Yandicooginamine in Western Australia.

The concept of in-pit crushing hasbeen around for manyyears but, in thecurrent market, with high energy and fuelcost, labour shortages, tire shortagesand emission standards, the trend towardsin- pit crushing is greater than ever.

Krupp was early into in-pit crushingbut others such as MMD, Metsoand Sandvik have followed. Some in-pitcrushing and conveying installations includeGrassberg, CVRD,Minera Dona Ins andCollahuasi in Chile andChina Shougang, among others.

Pebble crushing is an arduous dutyin a SAG mill circuit. The trend to installinglarger pebble crushers capable of crushingup to 70-100 percent of the new feedrate has been observed. The improvements in SAG milling efficiency with apebble crusher for some ores are nowwell established.

In Australia, these were pioneeredat Argyle on diamond ores and provedproblematic. HPGRs are emerging asan important new comminution processin mineral processing circuits, primarilybecause they offer substantial energysavings. There is good evidence fromprevious work that HPGR technologyis more energy-efficient than the typicaltumbling comminution machines, includingautogenous, semi-autogenous andll mills. HPGR technology has beenwidely used in the cement industry and,to a lesser extent, in the diamond industryand on iron ores, but rarely in the widermineral industry. This is set to changein the future environment of high energycosts.

In addition, the use of HPGR technologyhas the potential to provide significantcapacity increases in existing plantsbecause there is evidence that the HPGRproduct has a significantly lower BondWork Index in downstream ball millingand, therefore, will grind to the requiredsize more quickly and with reducedenergy. Furthermore, HPGR technologymay allow a simpler upstream processcompared with AG/SAG mills. Machineshave capacities up to 3000 t/h and cando similar work to an SAG mill at half theenergy consumption.

There is more care with sampleselection and representivity and comminutiontesting has become mandatory.There is less reliance on manufacturerscatalogues and a greater use ofconditional simulation. The comminutiontests available include JK DropWeight, Abrasive index and unconfined Compressive Strength (UCS) tests. There have been projectfailures and the industry as a whole has learnt from these. Theuses of variability testing and geometallurgy have also beenimportant advances.

Simulation packages have been developed that allowsimulation and optimization of crushing and grinding circuits.JKSimMet is an award-winning, general-purpose computer softwarepackage for the analysis and simulation of comminution and classification circuits in mineral processing operations. Itincorporates industrial strength models developed at theJulius Kruttschnitt Mineral Research Centre (JKMRC). The packageis designed for plant and development metallurgists who wishto apply process analysis techniques to characterize plant behavior,and design engineers who require process simulationmodels to assess design alternatives.

six trends in future mining industry toward success - eastman rock crusher

six trends in future mining industry toward success - eastman rock crusher

With the development of the mining industry and the increasing demand for mineral resources and their products, both developed and developing countries are considering the possession of resources and developing resources as strategic measures. As a result, the mining industry had developed many efficient, safe yet low-cost mining technologies and methods, so that keep up with the pace of advanced technology, as well as the increasingly strict enforcement of environmental protection regulations.

Take the Swedish Kiruna iron ore mine, for example. Kiruna iron ore is famous for producing high grade (more than 70% iron ore) and is one of the largest iron ore mines in the world. Its iron ore mining has been more than 70 years of history, has now been open-pit mining to underground mining. The intelligence of Kiruna iron ore mine is mainly due to the use of large-scale machinery and equipment, intelligent remote control system, as well as a modern management system, highly automated and intelligent mine systems, and equipment to ensure safe and efficient mining is the key.

At present, in the recovery of low-grade copper, gold ore, uranium ore, etc. have been widely used solubility technology, in the soil immersion technology in situ leachings, heap immersion and situ crushing leaching three categories.

The United States, Canada, Australia, and other countries handle 0.15% to 0.45% of low-grade copper ore, more than 2% copper oxidation ore, and 0.02% to 0.1% uranium ore are recycled by heap immersion and in situ blasting leachate.

In the United States, for example, there are more than 20 mines that use insitu blasting to leach copper. For example, Mike Mine in Nevada, Zonia Copper Mine in Arizona produces copper per day above 2.2t, Butt Mine and Copper Queen Mine in Montana produce 10.9 to 14.97t of copper, u.S. dissolved copper production accounts for more than 20% of total production, gold production exceeds 30%, and the majority of uranium production comes from dipping mining.

With the continuous reduction of resources, the depth of mining is getting deeper and deeper, mining depth to 1000m or less, bringing many in shallow mining did not encounter difficulties and problems, such as increased ground pressure, increased rock temperature, at the same time, lifting, drainage, support, ventilation and other difficulties also increased.

1) Boostability. Mining depth increased, the first encounter is the mines lifting capacity problem, the current lift machine lift the maximum height of more than 2000m, such as a Canadian lift of the deepest mine has reached 2172m deep, a gold mine in South Africa has a deep 2310.4m. At present, the ability to upgrade equipment has been able to fully meet the requirements of large-scale deep well mines.

2) Rock mild ventilation and cooling. The depth of mining increases, the rock temperature also increases, such as Japans Fengyu copper and zinc mine at the level of -600m (about 1200m from the surface) rock layer temperature has exceeded 100 degrees C, but many countries in the world stipulate that the underground temperature can not exceed 28 degrees C. Deep well mine generally adopts the increase of underground ventilation air volume and underground air cooling, that is, the use of air and water cooling 2 ways, the choice of one or both, in addition to trying to reduce the temperature, but also pay attention to reduce the cooling of underground machinery and equipment, underground diesel equipment cooling and underground cooling equipment itself cooling problems.

3) Ground pressure management and mining methods. Generally deep well mines should establish a complete set of ground pressure measurement and monitoring system, it is directly related to the mining production can be carried out smoothly and production costs. Rock explosion is a prominent problem encountered in deep well mining, in order to predict rock explosion, many mines have installed micro-seismic monitoring devices underground, such as the U.S. Rizhao Silver Mine on the 2254m level installed micro-seismic monitoring devices, 24h monitoring.

4) Self-ignition self-explosion. Deep well mining will also be due to the high temperature of the ore, resulting in the self-ignition of vulcanized ore and the phenomenon of self-explosion when filling explosives, but also to cause sufficient attention.

At this stage of Chinas non-coal mining mountain mining depth is generally not more than 700 to 800m, but in recent years there have been a number of buried depth of about 1000m of the deposit is being developed, the copper tomb non-ferrous metals company belongs to the Dongguashan copper deposit, Jinchuan two mining areas are included in it.

In foreign countries, especially in developed countries, comprehensive management measures are adopted for the mining environment. Waste water, waste gas, waste residue and dust, noise, etc. discharged from mines have strict technical standards, many low-grade mines, because the cost of environmental protection management is too large to build and put into operation.

At present, foreign emphasis is also on the establishment of waste-free mines and clean mines, Germanys Ruhr Industrial Zone Walsm coal mine is a successful example, with coal washing plant coal and coal power generation after burning coal ash and broken underground waste stone added cement by activation and stirring, with PM pump to the underground filling area, the mine does not discharge any solid waste.

1) Focus on forming a practical and reliable system. It is necessary to research and develop effective filling technology so that the filling operation and the mining operation cycle can be effectively combined. We should pay attention to the management of filling system.

2) Research can enable the existing system to achieve optimized design technology, study the composition of high-quality filling particle distribution, study in the hydraulic cyclone and crushing has been improved filling preparation process, research used to optimize the filling of the delivery technology such as pressure loss, wear, corrosion to optimize the overall design of filling system.

3) Strengthen the quantitative understanding of the preparation, transportation, charging and load deformation process of filling, and lay the foundation for safe, stable and efficient mining. At present, the international filling process is: water sand filling, dry filling, high water solid filling, glue filling. The glue filling is also divided into: segmented tail sand hydraulic filling (high concentration self-slip transport), other filling hydraulic filling (high concentration self-slip transport), full-tail edand body self-filling and full-tail sand paste pumpfilling. At present, the international recommendation is the whole tail sand paste pumpfilling.

At present, 12 mines in Canada have applied high concentration paste filling, South Africa and Australia also have a new paste filling system put into operation. The new filling process will be able to better meet the requirements of protecting resources, protecting the environment, improving efficiency and ensuring the development of the mine. Fillmining will have a wider outlook in the mining development of the 21st century.

Polymetallic nodules are deposited on the seabed at depths of about 3000 to 5000 m. A viable method of mining is necessary to mine. Therefore, the development of reliable mining methods in all countries of the world has given priority to the development of a large number of experimental studies, and some have even carried out deep-sea intermediate mining tests. From the late 1960s to the present, the ocean mining methods developed and tested in the world are mainly divided into continuous chain-to-chain bucket (CLB) mining methods, submarine remote control vehicle mining methods and fluid lift mining methods.

1) Continuous Chain Bucket (CLB) mining method. The method was proposed by the Japanese in 1967. The method is simple and mainly composed of mining ship, tow cable, cable bucket and tractor. According to a certain interval, the rope bucket is attached to the tow cable and put the human sea floor, the tow cable under the tow boat to do the rope bucket down, shovel ingress and uplink action, this stepless rope cycle operation constitutes a continuous acquisition loop. The main feature of the CLB is its ability to adapt to changes in water depth and keep it operating normally. But the clB method can only produce up to 100t/d. Far from meeting the requirements of industrial mining. As a result, the CLB mining law was abandoned in the late 1970s.

2) Submarine remote control vehicle mining method. This method was mainly proposed by the French. The submarine remote control vehicle is an unmanned diving mining vehicle, which is composed of four systems: mining mechanism, self-propelled propulsion, buoyancy control and ballast. Under the monitoring of the sea surface mother ship, the mining vehicle snuck into the sea floor in accordance with the instructions to collect nodules, filled with nodules surfaced and to the mother ship to receive the discharge of nodules, the sea mother ship can usually control several mining vehicles operating at the same time. The method of mining system investment, product value is not high, in a few decades without economic benefits, the French Ocean Tuberculosis Research and Development Association in 1983 stopped research, but this mining vehicle procurement principle is considered a promising acquisition technology.

3) Fluid lift mining method. At present, the international lysier is the fluid lift mining method, and the most industrial application prospects. The method is that when the mining vessel reaches the mining area, the collector and lift pipe are connected and gradually released to the marine vessel collection machine for the collection of nodules in the seabed sediments and for preliminary treatment, so that the water in the pipe moves upward at sufficient speed by hydraulic or hydraulic lift to transport the nodules to the offshore mining vessel.

With the advent of the sea in the 21st century, ocean mining technology is particularly important. The development of modern high-tech has laid a bridge for the development of ocean resources, and its formation and development will have a positive and far-reaching impact on the world marine economy, culture and human marine consciousness.

The development trend of mining technology in foreign mines is in addition to the six aspects mentioned above. There is also natural rock mining technology is becoming more and more perfect, the application is also expanding, in addition to rock drilling also has a large number of new technologies emerged, mining rock mechanics and engineering has been as an independent discipline. It is playing an increasingly important role in the construction and production of mines.

amc mining & crushing

amc mining & crushing

Our equipment forms a vital part of our business, and with that, we believe that by maintaining our equipment we are investing in the success and longevity of our business. We are constantly growing and maintaining our fleet of equipment thereby ensuring optimal production results and maximizing profit.

AMC prides itself in being able to assess each project based on its specific requirements and then providing the most effective and efficient solutions. We have also realised that our clients and projects mean more to us than just delivering solutions, its about building relationships that are based on trust, reliability and integrity. These types of relationships undoubtedly add to the success of any project.

Our suppliers play an integral part in the successful operation of our business. It is imperative that we have a well established and mutually beneficial relationship with our suppliers. Our current suppliers provide exceptional services, which in turn enable us to offer a better product to our clients.

AMC believes that its people are the backbone of its business, and its skilled workforce enhances product quality and services delivery. In order to help each employee reach their full potential AMC provides its employees with the opportunity to take part in its innovative Employee Development Programmes.

Our employees are remunerated at marked related levels, but AMC has become an employer of choice in the Mining and Crushing Industry due to its lucrative incentive schemes for extraordinary performance. AMC also provides employees with superior benefits and job security.

African Mining and Crushing will endeavour to preserve the health and safety of all persons affiliated with its activities, as well as the health and safety of any visitor. All work is to be performed under the direction and supervision of knowledgeable, suitably qualified staff, appointed in writing, accepting responsibility for the safe execution of the task at hand.

Management, employees, sub-contractors and visitors at African Mining and Crushing will, as a minimum, comply with all applicable health & safety legislation, as well as the Health & Safety Management Programme of African Mining and Crushing. Visible felt leadership is demonstrated at all levels within the organization

We do not only believe site rehabilitation to be necessary but constantly plan and scrutinize every new and existing project in order to minimize the impact that our activities have on the environment. We believe that this is an area where we have to be proactive and lead the industry by example.

We are committed to continually improving our environmental performance as an integral and fundamental part of our business strategy and operating methods. We will continually assess and minimize the impact that our plants and products have on the environment and the communities in which they operate. We will make both clients and suppliers aware of the environmental policy by which we operate and would urge them to do the same for sustainable growth and the well-being of future generations.

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lubricating the mining industry - crushing and quarrying world

lubricating the mining industry - crushing and quarrying world

In mining, heavy-duty and high-temperature lubricants, hydraulic fluids and multifunctional oils have to resist high mechanical and thermal loads as well as the rough ambient conditions. The industry is continuously seeking improved lubricant solutions to each part of its operational requirement, specifically because it has a direct bearing on the wear and tear of the equipment, which in-turn impact the life-span which impacts the profit margins. Apart from economic benefits, lubricants need to comply with special standards and safety regulations combined with eco-friendly considerations.

Reliable and cost efficient lubrication under extreme conditions requires not only the use of high-performance lubricants, but also expert knowledge with regard to their appropriate application. Lubricant manufacturers have continued to improve their products to meet the needs of bigger, faster machines. Although most lubricant suppliers are not lubrication system specialists, many have the resources to provide technical support, offering sound advice for selecting the products best-suited for the applications.

The products commonly used in mining equipment can be divided into three groups: heavy-duty lubricating oils, such as EP oils for enclosed gear drives; multipurpose engine, circulating and hydraulic oils for engine, bearing lubrication and fluid power; and general purpose grease, for normal industrial bearing applications and specialized mining products. Walking draglines may require lubricants for the very large plain bearings that support the entire frame of the unit as it moves through the walking process.

These lubricants may have a high concentration of lubricating solids or soft metals dispersed into a stiff grease and delivered in small bags (for the walking mechanism without an automatic delivery system) just ahead of the peak loading area. This grease is referred to as a Walking Cam lubricant.

An effort to reduce the number of lubricants on a machine has driven the development of multipurpose products designed to meet several different applications from a single lubrication system. The various components to be lubricated may include the open gears, guide rails, main table bearings and various smaller slides and bearings.

More recently, independent lubrication service consultants are becoming a viable alternative to the industry. Utilizing an independent consultant offers a mine the ability to purchase the product of choice based strictly on quality and product cost, but without any possible hidden costs of product-service combinations or cost-per-hour contracts.

The operators purchase the lube products for the equipment based on equipment criteria and purchase the service of a consultant based on experience and costs. This platform is a unique and upfront approach to product-service combinations. When considering an independent lubrication service consultant, check the individuals references supporting his/her abilities and knowledge.

As the industry continues to evolve, expect to see continued evolution in all aspects of the industry and allied fields. With global positioning satellites (GPS) offering the potential for remotely operated equipment, computer systems taking lubrication systems to new levels of control, manufacturers continuing to meet the demands of an ever-changing and competitive industry, one thing should always remain the same.

When it comes to the development and application of lubricating products, providing the cleanest possible environment, storing the products properly, reducing rehandling and applying the right product in the right amount, in the right place, at the right time will always be the necessary criteria, no matter how many times these practices are reinvented

Each piece of mining equipment made by different original equipment manufacturers (OEMs) has its specific lubrication requirements. OEMs define the minimum requirements for lubricants or greases, but not all products that meet these standards deliver the same level of performance.

Choosing the correct lubricant or grease often depends on a combination of the equipments design characteristics, operational parameters and environment. Factors like temperature, humidity and location (altitude/underground) all pose different challenges for lubrication. Below are three of the primary lubricant applications in the mining industry, along with some examples of specific lubrication challenges. In all cases, selecting the right lubricant is a critical first step in improving productivity and realising significant savings.

Engine wear as a result of metal-to-metal contact can occur at low speeds, high loads, or cold starts. The lubricant helps keep moving parts separated to avoid wear. At engine start-up, particularly in cold climates, the oil must remain thin enough to circulate quickly to protect critical components. Once the engine is operating under full load, the oil needs to remain thick enough and provide the necessary protection to help prevent abrasive wear.

In gear motors, the lubricant must help improve bearing life and give excellent protection against wear and pitting. Transmission oil helps keep moving components apart, such as gear teeth and rolling elements, thereby avoiding metal-to-metal contact and wear. Selecting a product that has the optimal viscosity for the application, along with the required additives to protect against wear and corrosion can have a major impact on equipment life. Viscosity and shear stability are also critical for performance at a range of temperatures.

Accumulation of soot in the engine can lead to oil thickening and abrasive wear. This is a particular challenge in underground mines, at high altitude, and when exhaust gas recirculation (EGR) is applied as an after-treatment system. Extended periods operating at idle load makes an engine susceptible to higher rates of soot generation.

Gases and acids are generated as a natural by-product of the combustion process. The lubricant neutralises these acids to help avoid corrosion. This is particularly important in engines with Babbit-based plain bearings, which can be very susceptible to acid attack.

Oxidation, soot accumulation and oil thickening, and the build-up of acids in the lubricant all contribute to oil aging. High quality synthetic engine oils with the right base oil and additive technology -including anti-oxidant additives -can maintain performance characteristics for longer time in the presence of contaminants and by-products. Oxidation stability and corrosion protection are also important to maintain oil performance. High quality transmission and gear oils with good oxidation resistance can resist degradation and break-down over time, thereby reducing downtime required for frequent oil changes

Powershift transmissions use a series of friction plates to help engage and disengage gears. The lubricant plays a critical role in transmitting frictional force, so its frictional properties are important for effective operation. Too little friction, and the plates can slip making gear changes difficult. Too much friction and excess heat generation can cause damage to equipment and shortened lubricant life.

Lubrication by Grease application in the mining sector can be a specialist technical area, where selecting the right grease for the right application can be critical to avoid costly equipment failures and unplanned downtime. This is particularly true for open gear applications, which are exposed to the elements in extreme conditions, and where contamination poses a significant challenge.

As open gears are exposed in all climatic conditions, the greases viscosity and pumpability is critical. In extreme cold, it must remain fluid enough to flow through grease lines to protect components, while in extreme heat it must remain thick and adhesive enough to stay on equipment surfaces.

Contamination ingress is the direct cause of about 40% of open gear failure. Exposure to high levels of dust, dirt, slurry, rain and snow means open gears require greases that can maintain an adequate lubricant film and continue to flow while flushing out contamination.

In differential gears, specific contact pressures can be so high that the transmission oil is squeezed away, allowing metal-to-metal contact. The use of extreme pressure additives helps prevent the contact areas of the teeth micro-welding together.

To help keep equipment operating at maximum efficiency, greases must be specially formulated to withstand the high load, extreme pressure, and shock-loading faced by mining machinery on a daily basis. Application Misapplication is the cause of around 40% of open gear failure. Even a perfect lubricant cannot protect equipment if it is not applied in the right volume at the right time. Lubrication systems must be maintained and fine-tuned to ensure correct application happens.

Two perfectly aligned gears have a contact ratio of 100%. If misalignment causes the contact ratio to drop below 85%, the load and stress on the gearing will increase. This overloads the gears and the lubricant film and can result in sub-surface cracks and pitting, which significantly reduces component life and may result in gear failure.

Norilsk Nickels Black Swan mine in Western Australia is active in sourcing nickel. An existing Shell customer, the company agreed to consider implementing a product rationalization project at the mine that aimed to reduce the number of products servicing the facility while improving operational performance. This would include changing all the gearboxes on-site from a mineral oil to a fully synthetic product, Shell Omala S4 GX. The changeover to new oil also had the potential to extend oil-drain intervals and equipment life while reducing sump temperature, downtime and electricity consumption.

Using Shell LubeAdvisor, the Shell Lubricants technical team presented a report to the mines engineering staff outlining the potential financial and operational benefits that could be realised by converting to Shell Omala S4 GX. Norilsk Nickel agreed to a 14-month project: the first seven months gathering baseline data and the second seven months trialling Shell Omala S4 GX and evaluating the operational benefits.

The trial of Shell Omala S4 GX in the gearboxes of the mines two grinding mills showed a 2.1% decrease in the electricity consumption of the units. Shell Omala S4 GX has the potential to last twice as long as a mineral oil and thereby to extend oil-drain intervals and reduce labour costs and downtime. Over 12 months, Norilsk Nickel estimated that changing the two grinding mills over to Shell Omala S4 GX 220 would save US$74,473 in waste disposal and electricity costs, even after the cost of the oil.

miningweekly.com | mining sector news | mining industry | crushing & screening

miningweekly.com | mining sector news | mining industry | crushing & screening

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4th September 2020 A PhD study on developing a roadmap for the South African titanium metal industry indicated that the South African titanium metal value chain should be expanded to include local TiCl4 and titanium metal powder production. The study was conducted at the Graduate School of Technology Management, at...

By: Mamaili Mamaila4th September 2020 Mining and quarrying equipment specialist Astec Industries Inc has completed a significant export order for a new aggregate crushing plant in Harare, Zimbabwe through its regional office in Johannesburg, in Gauteng.

28th August 2020 A call for further engagement with the Department of Mineral Resources and Energy (DMRE) regarding the 2019 Draft Review of Housing and Living Conditions Standard has stalled as a result of the Covid-19 pandemic and the subsequent lockdown in South Africa. The draft standard requires that mines...

By: Martin Creamer20th August 2020 The Electra Mining Africa Connect week will enable exhibitors to promote their products and services free of charge alongside industry-related informative webinars, media activations and product showcase opportunities from September 7 to 11. For the first time in 48 years, Electra Mining Africa...

10th July 2020 Diversified industrial group thyssenkrupp has extensive experience in materials handling and minerals processing circuits, and the service support of its own manufactured equipment. A fully owned subsidiary of thyssenkrupp, headquartered in Essen, Germany, thyssenkrupp Industrial Solutions South...

By: Marleny Arnoldi6th July 2020 Mining and quarrying equipment specialist Osborn has completed an export order to Kyrgyzstan, which extends its reach into the Commonwealth of Independent States (CIS) region. The equipment supplied by Osborn has been installed at the countrys second-largest gold mine, the Jerooy gold project.

By: Cameron Mackay3rd July 2020 Following growth in Australia, as well as expansions into other countries, Australian mining and heavy equipment trader Components Only is focusing on continuing its momentum in terms of global growth. About 30% of our revenue is now international. Our international expansion is twofold to...

3rd July 2020 The selection of suitable equipment for specific earthmoving tasks is critical, not only to optimise productivity, but to also ensure efficient capital expenditure, minimal downtime and safety on site, notes Equipment supplier HPE Africa. It is also critical that the equipment that is selected...

By: Shannon de Ryhove3rd July 2020 South African minerals processing company Multotec is expanding its global reach by investing in South America, where almost 30% of the worlds foreign direct investment is being funnelled. South America is a very important mining jurisdiction. Multotec Chiles official registration in 2014...

By: Marleny Arnoldi1st July 2020 Metso Minerals, a subsidiary of global industrial company Metso, has officially merged with Finnish-listed technology company Outotec. The merger has formed a leading process technology, equipment and services company serving the minerals, metals and aggregates industries. The combined company...

By: Theresa Bhowan19th June 2020 Power transmission products distributor Bearings International (BI) is supplying bearings manufacturer Dodge ISN bearings to the quarrying sector to address contamination the leading cause of premature bearing failure in the industry.

19th June 2020 Plant operators want to eliminate dust and spills on belts and transfers as well as minimise maintenance requirements of the conveyor system. Further, the ability of plants to efficiently cope with the challenges of moist and sticky materials related to quarrying is also desired.

19th June 2020 Earthmoving equipment supplier HPE Africas McCloskey S250 screener one of the largest tracked-mounted mobile vibratory screening plants available has been designed for highly-efficient aggregate material screening.

cyber-security risks in mining industry - crushing and quarrying world

cyber-security risks in mining industry - crushing and quarrying world

Although numerous consumer companies have been thrust into the spotlight due to data breaches, the alarm bell has been slow to sound within the mining sector. For years, mining organizations largely had a false sense of security, believing they could operate under the radar of cyber criminals who had more lucrative targets to pursue. Why would malicious actors hack a mining operation when they could attack a consumer organization that moves financial data? Today, that reasoning has become as faulty as a patch on decades-old software.

The mining industry is moving into its next stage of evolution, which is sometimes referred to as intelligent mining. As detailed in the recent Deloitte report, Intelligent Mining: Delivering real value, this entailsin addition to broader organizational changerapidly integrating robotics, automation, and the Internet of Things (IoT) into the operational environment. At the same time, the interest of cyber criminals in industrial operations has increased over the last decade, while the motives for their actions have become more diffuse. Malicious hacking, ransomware attacks, electronic fraud, data leaks and corporate espionage have become prevalent worldwide. These illicit activities are often driven by financial, political, or competitive objectivesor merely by the desire to cause disruption.

The combination of greater connectivity and proliferating threat vectors has already resulted in cyber attacks that have compromised both production and safety. These attacks have made cyber security a hot discussion topic within boardrooms around the globe, and now a growing number of organizations are developing transformation programs to address these new operational threats. However, making operational processes secure, vigilant and resilient is a challenge. For example, deploying the organizations existing cyber capabilities within the operations environment requires harmonizing two cultures, which is challenging. In addition, the operations environment demands continuous availability, along with tailored technical solutions that are not always easy to secure.

Solving these challenges requires a good understanding of both engineering and information technology (IT) disciplines as well as leading, sector-specific cyber security practices. This article shares the understanding weve culled from our field experience, including lessons learned in helping mining companies to go beyond safety in securing their industrial control systems (ICS).

Critical infrastructure relies on Industrial Control Systems (ICS) to maintain safe and reliable operations. Engineers have successfully designed and deployed ICS with safety and reliability in mind, but not always security. Why? Originally, there was little need for it. Fit-for-purpose, isolated operational systems were the order of the day. Since these operational systems were not integrated to enterprise systems or even to each other, the risk of a large-scale cascading failure due to an attackcyber or otherwisewas extremely remote.

Fast forward 20 years, and digitization and IoT has turned the most basic assumptions about operational security upside down. Today, all sorts of industrial facilities, including mine sites, mineral processing plants, and remote operations centers are vulnerable to cyber attacks. These vulnerabilities span critical electrical infrastructure, connected distributed control systems, programmable logic controllers (PLCs), supply chain partners, and more. Even a shaft mine with little internet connectivity underground is vulnerable to cyber-attacks on the aboveground electrical system, which could put the mines ventilation system at risk. Even more disconcerting, mitigating this type of cyber threat may be completely outside of the companys control if the mine is reliant on the broader electricity grid rather than on its own distributed energy resources, such as solar panels or diesel generator sets.

Across multiple vectors, operational systems can now be compromised by external or internal hackers, causing safety or production failures and increasing commercial risk. Although ICS are typically designed to failproof, the increasing sophistication of cyber criminals heightens the risk of catastrophic incidents, along with the magnitude of the impacts in terms of cost, safety, reputation and commercial or financial losses.

As mining companies begin to grapple with the implications of an inter-connected operational environment, their corporate back-office systems are simultaneously coming under fire. Nation states, local activist groups, and even competitors have shown a keen interest in stealing intellectual property and proprietary information, such as exploration data, company valuations and other information pertaining to mergers and acquisitions. Often the goal is to gain an edge in negotiations or to influence business dynamics.

Threats such as these have made cyber security a top concern among senior leadership and boards of directors, and like other industries, the Energy, Resources and Industrials (ER&I) industry has been working to shore up its defenses. Such incidents inspired a group of Canadian mining companies to start the Mining and Metals Information Sharing and Analysis

Center (MM-ISAC). Launched in April 2017, the non-profit industry-owned Center is open to all companies in the mining and metals industry. It allows member companies to share critical cyber security information through secure channels enabling them to benefit from this intelligence at a reasonable cost. Importantly, the Center hints at the type of information sharing and resource pooling that could help the sector to combat cyber threats more effectively, similar to the collective approach taken by the financial sector.

While the mining industry has suffered data breaches and loss of intellectual property, it has escaped a major operational catastrophe thus far. However, this good fortune may not last unless mining companies expand their cyber security programs to protect operational as well as back-office systems and embrace the new level of intra-industry collaboration required to stay ahead of the rapidly evolving threat landscape. At a minimum, companies will need to think more broadly about what cyber security entails. To date, mining companies have been primarily focused on protecting corporate, as opposed to operational, systems and data. Thats because the IoTwhere production can be controlled from a smart phone, for instanceis relatively new, gaining momentum over the last decade, and because operational systems are inherently different, requiring engineering know-how, in addition to IT expertise, in order to secure them appropriately. Today, an approach is needed that brings together IT and engineering to address cyber security programmatically and sustainably.

One of the main factors that makes it so difficult to secure ICS is that they were not designed to be connected, yet today they are networked. Digitization of operational processes in the mining industry has led to new opportunities to improve productivity and to drive down costs. However, the convergence of operational and business systems has also opened up the enterprise to a whole new array of cyber risks.

As these examples demonstrate, cyber threats can come from many directions, including internal actors aiming to sabotage production, competitors seeking to cause brand damage, and external parties, such as activist groups, wanting to shut down operations.

However, not all vulnerabilities stem from the technologies themselves. Diverse mine types and locations, coupled with the decentralized structure of many companies, also pose a challenge. For instance, it is not uncommon for a mining organization to be running 10 different versions of an industrial control system across 10 different mines, each having different degrees of internet connectivity. In this type of environment, it is not uncommon for the corporate Chief Information Security Officer (CISO) to have little control over site-specific security procedures.

Behavioral aspects additionally come into play. Like sometimes a lack of security awareness within the organization can inadvertently expose systems to cyber attacks, such as when employees bring portable media that is infected with malware into the environment. In many operations employees simply believe that their systems are an unlikely target, thus they are reluctant to buy into the need to change their behaviors and implement new security protocols. After all, not long ago they could safely assume that all equipment components were trustworthy, which is no longer the case since digital sensors and controllers can be manipulated to provide false input and misguiding status information. Another outdated assumption is that process failures are mainly caused by weather conditions, human error and equipment fatigue, and not necessarily malicious manipulation of the system by those intending to inflict harm.

Whether a cyber breach is intentional or unintentional, the consequences can be grave, ranging from compromising confidential data to triggering system failure or shutdown. This can result in decreased revenue, reputational damage, environmental disaster, legal penalties, and in extreme cases, loss of life.

Its easy to see why integrating effective and comprehensive cyber security controls into ICS is necessary, if not increasingly becoming mandatory. But to get there, companies must find a way to reconcile the divergent points of view of IT and operations: ICS specialists do not always fully understand modern IT security risks, just as IT security specialists often do not completely comprehend the industrial processes supported by ICS.

For over 50 years, safety was the primary motivation behind designing and deploying controls for physical production processes. While this motivation is still there keeping processes in a safe and operational state the landscape of potential disruptions now encompasses the cyber domain. This now requires a unified program to address cyber security systematically across the business and operations. Although building and implementing a program of this nature is a multi-year, transformational effort, each phase of the initiative should have the same objective in mind: moving up the maturity scale to create an ICS environment that is secure, vigilant, and resilient.

Being secure is about preventing system breaches or compromises through effective, automated controls and monitoring. But, its not feasible to secure everything equally. Critical assets and infrastructure and their associated ICS would obviously be at the top of the list, but its important to remember that theyre not isolated components. Theyre part of larger supply chains, so its essential to shore up weaknesses throughout end-to-end processes. This can involve many layers and types of controls, ranging from installing firewalls to hardening sensors such as on drilling machines, excavators, earth movers, crushing and grinding equipment and processing plants. Systems need to be designed to consider that the entity operating an asset may not be the only organization with rights to data. Service and supply companies and equipment vendors may also be given visibility into operational and equipment performance data in order to improve the services they can offer. Unless properly structured, this might provide an opportunity for unforeseen data leakage or system weaknesses, which could be exploited by third parties. It is essential to build control and monitoring systems with clearly defined data access rights and the ability to identify when these are contravened.

Security alone is not enough. It must be accompanied by vigilance, or continuous monitoring to determine whether a system is still secure or has been compromised. Worthwhile efforts to be vigilant start with an understanding of what you need to defend against. There are discernable threat trends in the mining industry, which provide a good starting point for understanding the types of attacks being launched against ICS. These trends, however, need to be supplemented by an understanding of your organizations specific business risks in order to anticipate what might occur and design detection systems accordingly.

In the past few years, the mining industry has seen the traditional boundaries between corporate IT and ICS largely disappear. Today, the evolution continues with the pursuit of intelligent mining to tackle the dual sector challenges of declining ore grades and operating efficiency. Beyond digitizing mining operations, intelligent mining is about making informed decisions through accurate, complete and timely information, which requires forging new connections across previously isolated mines sites and functional business silos. As this interconnectedness marches on, so does the frequency and sophistication of cyber attacks. However, most companies have not kept pace in terms of their preparedness. The call to bridge the cyber-readiness gap has never been louder, with growing public awareness of cyber crime and the potentially disastrous impact it can have on critical infrastructure. The place to start is assessing the maturity of your cyber security controls environment.

Going beyond traditional operational safety considerations to implement a secure, vigilant and resilient program is not only essential for enhancing a mining companys ability to protect operational integrity amid a growing range of cyber threats but also to achieve operational excellence by taking advantage of the productivity benefits offered by a digitized, fully integrated ICS environment.

crushing and milling | mining of mineral resources | siyavula

crushing and milling | mining of mineral resources | siyavula

In this chapter we build on what was done in the previous two chapters. After learning that rocks contain minerals, we now explore how the minerals may be extracted so that they may be utilised. Mining plays an important role in the wealth of a country. Learners will therefore learn about the mining industry in South Africa and the impact that mining may have on a country and the globe.

The mining industry is an important industry in South Africa. It involves a number of industries working together. Exploration is followed by excavation, which is followed by crushing and milling to reduce the size of the rocks. This is followed by extraction (removing the valuable minerals from the ore) and finally refining. Each of these processes are discussed in this chapter. The idea is not that learners should know all the terms off by heart, but rather that they grasp the bigger picture. A number of different processes are needed with each one dependent on the efficiency of the step before. The flow diagram exercise towards the end of the chapter is meant to consolidate the chapter content and help learners realise the continuous nature of many industrial processes.

A research project is also included in this chapter. Let the learners choose one industry and research the different aspects of mining covered in this chapter for their chosen industry. The following mining industries can be researched: gold, iron, copper, diamond, phosphate, coal, manganese, chromium or platinum group metals (PGMs). Learners could also choose their own.

The projects need to be handed out in the beginning of the term/chapter. Learners can then present their projects at the end of the chapter, by doing a poster or an oral, or both. For the orals, we suggest you work with the language department so that learners can be assessed there as well. If posters are done, then we suggest you put these up for display for the whole school to see. Learners can stand at their posters during breaks where learners from other grades have the opportunity to come and have a look at their work and ask questions about it.

The project has a two-way purpose, firstly for learners to continue learning about doing research, finding information and presenting the information to others, and secondly, for learners to explore careers in this industry. Part of what they should include in their research is a section on careers in mining.

In the previous two chapters you have learnt about the spheres of the Earth especially the lithosphere. The lithosphere consists of rocks, which contain minerals. Minerals are natural compounds formed through geological processes. A mineral could be a pure element, but more often minerals are made up of many different elements combined. Minerals are useful chemical compounds for making new materials that we can use in our daily lives. In this chapter we are going to look at how to get the minerals out of the rocks and in a form that we can use. This is what the mining industry is all about.

You already know that minerals in rocks cannot be used. Many processes are used to make minerals available for our use. We need to locate the minerals. We must determine whether these concentrations are economically viable to mine. Rocks with large concentrations of minerals, are called ores. Mining depends on finding good quality ore, preferably within a small area.

The next step is to get the rocks which contain the mineral out of the ground. Once the ore is on the surface, the process of getting the mineral you want out of the rock can start. Once the mineral is separated from the rest of the rock, the mineral needs to be cleaned so that it can be used.

This project should be handed out in the beginning of the chapter so that learners have time to work on it. Information for the project is provided in the sections in the chapter, but learners also need to find information on their own. Guiding questions are provided to help learners.

One of the most important steps in mining is to find the minerals. Most minerals are found everywhere in the lithosphere, but in very, very low concentrations, too low to make mining profitable. For mining to be profitable, high quality ore needs to be found in a small area. Mining exploration is the term we use for finding out where the valuable minerals are.

Today technology helps mining geologists and surveyors to find high quality ore without having to do any digging. When the geologists and surveyors are quite sure where the right minerals are, only then do they dig test shafts to confirm what their surveying techniques have suggested.

In all these methods we use the properties of the minerals and our knowledge of the lithosphere to locate them underground, without going underground ourselves. For example, iron is magnetic so instruments measuring the changes in the magnetic field can give us clues as to where pockets of iron could be.

Exploration methods are used to find, and assess the quality of mineral deposits, prior to mining. Generally a number of explorative techniques are used, and the results are then compared to see if a location seems suitable for mining.

Remote sensing is the term used to gain information from a distance. For example, by using radar, sonar and satellite images, we can obtain images of the Earth's surface. These images help us to locate possible mining sites, as well as study existing mining sites for possible expansion.

Rare earth elements are a set of 17 elements on the Periodic Table, including the fifteen lanthanides and scandium and yttrium. Despite their names, they are found in relatively plentiful amounts in the Earth's crust.

Geophysical methods make use of geology and the physical properties of the minerals to detect them underground. For example, diamonds are formed deep in the Earth at very high temperatures, in kimberlite pipes of igneous rock. The kimberlite pipe is a carrot shape. The first kimberlite pipe to be detected was in Kimberley in South Africa. The pipe was mined, eventually creating the Big Hole.

Geochemical methods combine the knowledge of the chemistry of the minerals with the geology of an area to help identify which compounds are present in the ore and how much of it is present. For example, when an ore body is identified, samples are taken to analyse the mineral content of the ore.

When colonialists arrived, they realised the potential mineral wealth of South Africa as gold, and later diamonds, were discovered. They ruthlessly took land from the local people wherever minerals were found, completely ignoring their right to ownership and access.

De Beers purchased the mining rights and closed all access to diamond mining areas. Anyone entering the area would be prosecuted and the sale of so-called 'illegal' diamonds was heavily punished. Other large mining companies have tried to claim the right to the minerals that they mine.

Once the ore body has been identified, the process of getting the ore out of the ground begins. There are two main methods of mining - surface mining and underground mining. In some locations a combination of these methods is used.

Surface mining is exactly what the word says - digging rocks out from the surface, forming a hole or pit. In South Africa, this method is used to mine for iron, copper, chromium, manganese, phosphate and coal.

Let's look at coal as an example. For surface mining, the minerals need to be close to the surface of the Earth. Most of the coal found in South Africa is shallow enough for surface mining. Usually the rocks are present in layers. To expose the coal layer, the layers above it need to be removed. The vegetation and soil, called the topsoil, is removed and kept aside so that it can be re-deposited in the area after mining. If there is a layer of rock above the coal face, called the overburden, this is also removed before the coal can be excavated. Once all the coal has been removed, the overburden and topsoil are replaced to help in restoring the natural vegetation of the area. This is called rehabilitation.

There is a growing emphasis on the need to rehabilitate old mine sites that are no longer in use. If it is too difficult to restore the site to what it was before, then a new type of land use might be decided for that area.

When you mine you are digging into solid rock. The rock needs to be broken up into smaller pieces before it can be removed. Holes are drilled in the rock and explosives, like dynamite, are placed inside the holes to blast the rock into pieces. The pieces are still very large and extremely heavy. The rocks are loaded onto very large haul trucks and removed. Sometimes the rocks (ore) are crushed at the mining site to make them easier to transport.

Mining trucks are enormous. They are up to 6 meters tall, that's higher than most houses. These trucks can carry 300 tons of material and their engines have an output 10-20 times more powerful than a car engine.

Often the minerals are not found close to the surface of the Earth, but deeper down. In these cases underground mining, also called shaft mining, is used. Examples of underground mining in South Africa are mining for diamonds, gold and sometimes the platinum group metals (PGM).

The PGMs are six transition metals usually found together in ore. They are ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir) and platinum (Pt). South Africa has the highest known reserves of PGMs in the world.

Sometimes the ore is very deep, which is often the case with diamonds or gold ore. In these cases mine shafts go vertically down and side tunnels make it possible for the miners and equipment to reach the ore. A structure called the headgear is constructed above the shaft and controls the lift system into the vertical shaft. Using the lift, it can take miners up to an hour to reach the bottom of the shaft.

The TauTona Mine in Carletonville, Gauteng is the world's deepest mine. It is 3,9 km deep and has 800 km of tunnels. Working this deep underground is very dangerous. It is very hot, up to 55C. To be able to work there, the air is constantly cooled to about 28 C using air-conditioning vents.

South Africa is a world leader in the gold mining industry. We have been doing gold mining for more than a century and our mines are the deepest in the world. Until 2010 we were the leading producer of gold in the world. Gold is a lustrous, precious metal which has a very high conductivity.

Yes it is, the mines are very deep, of the deepest in the world. Mining deep underground is difficult and dangerous because of the heat and lack of oxygen. Rocks can also collapse because of the pressure.

One of the methods used in underground mining is called room and pillar, and is often used for mining coal. Part of the mine is open to the surface and part of it is underground. The coal face is dug out, but pillars of coal are left behind to keep the tunnels open and support the roof. Machines called continuous miners are used to remove the coal. The coal is loaded onto conveyor belts and taken up to the surface for further crushing.

This section looks at methods to get very large rocks crushed and ground until it is as fine as powder. The first concept that needs to come across here is that minerals are inside rocks and by crushing rocks, the minerals are exposed at the surface of the rock fragment. Only then can chemicals be used to extract the mineral. An analogy with a choc chip biscuit is used to demonstrate this principle. The second concept is that a lot of energy is needed to break rocks. This is a very energy-intensive step in the mining industry, and one of the reasons why mining is so expensive.

This lesson can be introduced by demonstrating the principle explained above to the class. Use choc chip biscuits and crush them with your fingers. This is to get the minerals (choc chips) out. The next step is to separate the choc chips from the crumbs - also a step in the mining process.

Mineral crystals are spread throughout rocks, just like chocolate chips are spread throughout a choc chip biscuit. Sometimes we can see the chocolate chips from the outside, but most of the time the chips are not visible because they are inside the biscuit.

The only way to find out how many choc chips there are is to crush the biscuit. In the same way we can sometimes see mineral crystals from the outside of the rock, but mostly we don't know what minerals there are and and what concentrations are inside the rock. The only way to find out is to break the rock into smaller and smaller pieces.

Once we have crumbled the choc chip biscuit, the chocolate pieces can be separated from the crumbs. In the same way in the mining process the valuable minerals can be separated from the unwanted rock. The unwanted rock is called waste rock.

Let's look at an example. You have learnt in the previous chapter that copper minerals are found in rocks. In South Africa, the Bushveld Igneous Complex is an area which stretches across the North West and Limpopo Provinces. Igneous rock with high mineral content is found here. Here they mine for PGMs, chromium, iron, tin, titanium, vanadium and other minerals using open pit and underground mining. The rocks from the mines are transported by conveyor belts to crushers. Jaw crushers and cone crushers break the huge rocks into smaller rocks.

You can demonstrate this to your class by placing some pieces of broken up biscuit into a plastic container with some marbles or ball bearings. Place the lid on the container and then shake it so that the marbles help to crush and break up the biscuit pieces even further.

This process of reducing the size of the rocks requires a lot of energy. Just image how hard it is to break a rock. How much more energy do you think is needed to crush a rock until it is like sand? This is one of the steps in the mining process that is very expensive because energy is needed to drive the process.

Most minerals are found as compounds in rocks. Only a few minerals are found in their pure form, in other words not bound to any other element. Examples of minerals found in their pure form are gold and diamonds (diamonds consist of the element carbon).

Some rocks are used as is, and do not need to be crushed into powder, or involved in minerals extraction. For example phosphate rock itself can be used as a fertiliser, or it can be used to make phosphoric acid. Sand, or the mineral silicon dioxide (SiO2) is used in the building industry. Coal found in sedimentary rock, is crushed into the appropriate size and used as fuel for electricity generation or the iron-making process.

Before the minerals can be used, they need to be separated from the waste rock. A number of different separation techniques are used. These techniques are based on the properties of the minerals. Different minerals are often found together, for example copper and zinc, gold and silver or the PGMs. A combination of techniques are used to separate the minerals from the waste and then the minerals from each other.

Sorting by hand is not a very effective method to separate out the minerals you want. It can only be used in exceptional situation or by individuals, for example many people mine for alluvial diamonds by hand in rivers in Angola. It is a cheap and easy process to do individually, but it is not feasible on an industrial scale.

Iron is a metal with magnetic properties. Iron ore can be separated from waste rock by using magnetic separation techniques. Conveyor belts carry the ore past strong electromagnets which remove the magnetic pieces (containing the iron) from the non-magnetic waste. How do you think this works? Study the following diagram

The magnetic iron ore will fall into the container on the right as it is attracted to the magnetic roller and travels around the bend of the magnet for a longer period, whereas the non-magnetic waste drops straight down due to gravity, as the magnet turns, and falls into the first container on the left.

One of the first methods for mining gold was that of panning, a technique where ore is mixed with water and forms a suspension. When it is shaken, the dense particles of gold sink to the bottom and could be removed.

Let the learners work in groups of three. The value of the activity is the process of doing it, and not so much the end product. Learners will want to separate every single bead in the process and this is not possible, nor does it happen in the mining industry. Valuable materials do end up as waste.

When choosing beads to separate, ensure that there are a variety of shapes, round and flat, small and large. Most plastic beads will float on water, but metallic ones will sink. The piece of carpet is provided to make the tray rough, but still smooth enough for round beads to roll off, and flat beads to stick. Choose the smallest flattest beads to represent the valuable materials.They will remain on the carpet in the tray more easily.

To separate by density, learners can drop the beads into water - some beads will float and others will sink. To separate by size, learners can use the mesh and let the smaller beads fall through into the cup, with the larger ones staying behind.

As an extension, include some beads which are identical in shape and size, but different colours. At this point, learners will want to hand sort them. Tell learners that hand sorting, although effective and is used by individuals, it is a very time-consuming process and therefore almost never done in the mining industry. Ask learners if they have any other ideas. This is where chemical properties come in. For example, tell learners that one colour bead reacts with an acid and the other does not. Get learners to discuss how they would then separate the beads knowing this. A real world example is that silver reacts with chlorine, but gold does not.

As you have seen in the activity, separating a mixture can be done using different properties, depending on the different properties of the beads. There could be a number of different ways to separate the beads depending on which type of bead you want to select (considered to be the most valuable ones).

Size separation is used frequently in mining to classify ore. For example, when iron ore is exported, it needs to be a certain size to be acceptable to the world market. Coal that is used in power stations also needs to be a certain size so that it can be used to generate electricity effectively.

Flotation makes use of density separation, but in a special way. Chemicals are added to change the surface properties of the valuable minerals so that air bubbles can attach to them. The minerals are mixed with water to make a slurry, almost like a watery mud. Air bubbles are blown through the slurry and the minerals attach to the bubbles. The air bubbles are much less dense than the solution and rise to the top where the minerals can be scraped off easily.

The focus of this activity is to illustrate the principle of flotation and for learners to practice explaining their observations. They will have to apply what they know about density to be able to explain what they see. This activity can also be modified by letting the learners predict what they think will happen before they add the peanuts and raisins to the tap water; and again before they add it to the soda water. The outcome might not be what they expected and the value of the activity is for them to try to explain what they see.

The activity can be done as a classroom demonstration, but it is more effective if done by the learners in pairs. The one learner can use the tap water, and the other the soda water. A suggestions is to buy packets of peanuts and raisins separately, otherwise oil from the peanuts can coat the raisins, causing some of the raisins to rise. The raisins can also be rinsed in acidulated water because they are often dressed with oil before sale for visual enhancement.

Learners should observe that the peanuts and raisins sink to the bottom in the tap water and remain there since they are more dense than water. However, in the soda water, the peanuts and raisins initially sink to the bottom, but then the peanuts start to rise. Small bubbles from the soda water attach to the peanuts' oily surface and cause them to rise to the surface.

The methods mentioned so far are all physical separation methods. Sometimes they are sufficient to separate minerals for use, like coal or iron ore. But more often the element that we are looking for is found as a chemical compound, and so will have to be separated by further chemical reactions. For example, copper in Cu2S or aluminium in Al2O3. What is the name for the force that is holding atoms together in a compound?

Once the compound is removed from the ore, the element we want needs to be separated from the other atoms by chemical means. This process forms part of refining the mineral, as you will see in the next section.

There are many different methods used to concentrate and refine minerals. The choice of methods depends on the composition of the ore. Most of the methods however, make use of chemistry to extract the metal from the compound or remove impurities from the final product. We will discuss the extraction of iron from iron ore as an example.

Iron atoms are found in the compounds FeO, Fe2O3 and Fe3O4 and in rocks like haematite and magnetite. South Africa is the seventh largest producer of iron ore in the world. Iron has been mined in South Africa for thousands of years. South African archaeological sites in Kwa-Zulu Natal and Limpopo provide evidence for this. Evidence of early mining activities was found in archaeological sites dating mining and smelting of iron back to the Iron Age around 770 AD.

The first iron mining techniques used charcoal which was mixed with iron ore in a bloomery. When heating the mixture and blowing air (oxygen) in through bellows, the iron ore is converted to the metal, iron. The chemical reaction between iron oxide and carbon is used here to produce iron metal. The balanced chemical equation for the reaction is:

This extraction method is still used today. The bloomery is replaced with a blast furnace, but the chemistry is still the same. Iron ore, a type of coal called coke (which contains 85% carbon) and lime are added to the top of the blast furnace. Hot air provides the oxygen for the reaction. The temperature of a blast furnace can be up to 1200C. The reaction takes place inside the furnace and molten iron is removed from the bottom. Lime (calcium carbonate or CaCO3) is added to react with the unwanted materials, such as sand (silicon dioxide or SiO2). This produces a waste product called slag. The slag is removed from the bottom and used for building roads. Iron is used to make steel. Hot gases, mainly carbon dioxide, escape at the top of the furnace.

For safety reasons, this experiment should rather be demonstrated. Ensure that you wear safety glasses when performing this experiment. It is quite easy to do, but takes a long time to actually react. The blow pipe needs to redirect the flame into the hollow in the block. Blow through the top of the blue part of the flame. Use a straw to extend the blow pipe so that you can stand a bit further away from the flame. Ensure that a steady stream of heat gets right into the middle of the mixture so that it glows red hot for a while. The video link in the Visit box also shows how the experiment is performed (and the mistakes made). The product can clearly be seen in the video.

In this experiment carbon was used to remove the oxygen from the lead(II) oxide. The carbon and oxygen form carbon dioxide, and the lead is left behind as a metal. This is the same process that is used in iron extraction in the blast furnace, that we discussed above. Coke, which is mainly carbon, removes the oxygens from the iron(III) oxide to form carbon dioxide and leaves behind the iron metal.

The iron that is formed in the blast furnace often contains too much carbon - about 4% where it should contain not more than 2%. Too much carbon makes the iron brittle. To improve the quality of the iron, it needs to be refined by lowering the amount of carbon. This is done by melting the metal and reacting the carbon with pure oxygen to form carbon dioxide gas. In this way the carbon is burned off and the quality of the iron improves. The iron can now be used in the steel-making process. Carbon reacts with oxygen according to the following chemical equation:

Most minerals go through chemical extraction and refining processes to purify them for use in making materials and other chemical products. These are then distributed to where they are needed, for example, coal is distributed to coal power stations and slag is distributed to construction groups for building roads. The mining industry supplies the manufacturing industry and the chemical industry with its raw materials, for example iron is distributed to steel manufacturing industries.

Long before diamonds were discovered in the Kimberley area and the Gold Rush in Pilgrim's Rest and Witwatersrand areas in the late 1800s, minerals have been mined in South Africa. At Mapungubwe in the Limpopo Province evidence of gold and iron mining and smelting was found which dates back to the early 11th century AD. However, it was the large scale mining activities that accelerated the development of the country.

South Africa has a wealth of minerals. We are the world's largest producers of chromium, manganese, platinum, vanadium and andalusite; and the second largest producer of ilmenite, palladium, rutile and zirconium. We are the third largest coal exporter, fifth largest diamond producer and seventh largest iron ore producer. Up to 2010 we were the world's largest gold producer, but our gold production has declined steadily over a number of years. We are currently fifth on the list of gold producers.

The Bushveld Igneous Complex has the world's largest primary source of platinum group metals, indicated on the map in light blue. It is one of the most important mining areas in South Africa due to its abundance of minerals.

Learners need to develop their own symbols for each mineral that is mined, and also colour code the map. The map is blank and so they must find out where each town is located and add it to the map. Let them also fill in the name of the city/town/area in which they live. If there are mining activities in your area which is not indicated on this table, let the learners add it to the list. The list provided is not exhaustive, but it is still fairly long. If you want to make the activity simpler, learners can also chose a certain number of minerals to represent.

There are two types of diamond mining, alluvial (which is found on the coast or in inland rivers which have washed through kimberlite pipes) and kimberlite (which is found inland). What is the link between these two types of diamond mining?

This activity is meant to consolidate the knowledge from this chapter. Each industry will have its own unique flow diagram. The idea is for the learners to realise that it is a continuous system where the one process feeds into the next one to produce a useful end product. This activity links up with the research project and should give learners a good guide for doing and presenting their research projects.

Coal mining: Finding coal seams through exploration in Mpumalanga, Free State and KwaZulu Natal mining for coal using open pit mining removing the coal by blasting and drilling loading onto haul trucks and removing from mine crushing the coal sorting into different sizes distribution to power stations electricity generation

Mining has played a major role in the history of South Africa. It accelerated technological development and created infrastructure in remote areas in South Africa. Many small towns in South Africa started because of mining activity in the area. It also created a demand for roads and railways to be built. Most importantly it created job opportunities for thousands of people. Even today many households are dependent on the mining activities for jobs and an income. Mining is an important part of our economic wealth. We export minerals and ore to many other countries in the world.

Mining activities also have a negative impact on the environment. In many cases the landscape is changed. This applies particularly to surface mines (open pit mines), where large amounts of soil and rock must be removed in order to access the minerals. The shape of the landscape can be changed when large amounts of rocks are dug up from the Earth and stacked on the surface. These are called mine dumps. Open pit mines also create very large unsightly and dangerous holes (pits) in the ground that change the shape of the land.

Air and water pollution can take place if care is not taken in the design and operation of a mine. Dust from open pit mines, as well as harmful gases such as sulphur dioxide and nitrogen dioxide, could be released from mining processes and contribute to air pollution. Mining activities produce carbon dioxide. Trucks and other vehicles give off exhaust gases.

If the mining process is not monitored properly, acid and other chemicals from chemical processing can run into nearby water systems such as rivers. This is poisonous to animals and plants, as well as to humans who may rely on that water for drinking.

An example are pollutants (dangerous chemicals), called tailings, left over from gold mining which pose a threat to the environment and the health of nearby communities. Dangerous waste chemicals can leak into the groundwater and contaminate water supplies if the tailings are not contained properly.

There are no specific answers for this activity. It is an open discussion. We suggest that you discuss the impact of mining in South Africa through this activity. The idea is that learners should come up with all the issues and think about the impact of what we as humans do. The answer to solving the issues is not necessarily to close down all mining activity.

Use the following concept map to summarise what you have learnt in this chapter about mining of mineral resources. What are the three types of mining that we discussed in this chapter? Fill these into the concept map. Remember that you can add in your own notes to these concept maps, for example, you could write more about the environmental impacts of mining.

Phalaborwa is home to one of the largest open pit mines in the world. The original carbonate outcrop was a large hill known as Loolekop. Archaeological findings at Loolekop revealed small scale mining and smelting activities carried out by people who lived there long ago. An early underground mine shaft of 20 meters deep and only 38 centimeters wide were also found. The shafts contained charcoal fragments dating the activities to 1000 - 1200 years ago.

In 1934 the first modern mining started with the extraction of apatite for use as a fertiliser. In 1946 a well known South African geologist Dr. Hans Merensky started investigating Loolekop and found economically viable deposits of apatite in the foskorite rock. In the early 1950s a very large low grade copper sulfide ore body was discovered.

In 1964 the Phalaborwa Mine, an open pit copper mine, commenced its operations. Today the pit is 2 km wide. Loolekop, the large hill, has been completely mined away over the years. A total of 50 different minerals are extracted from the mine. The northern part of the mine is rich in phosphates and the central area, where Loolekop was situated, is rich in copper. Copper with the co-products of silver, gold, phosphate, iron ore, vermiculite, zirconia and uranium are extracted from the rocks.

The open pit facility closed down its operation in 2002 and has now been converted to an underground mine. This extended the lifetime of the mine for another 20 years. The mine employs around 2500 people.

2000 million years ago this area was an active volcano. Today the cone of the volcano is gone and only the pipe remains. The pipe is 19 km2 in area and has an unknown depth, containing minerals like copper, phosphates, zirconium, vermiculite, mica and gold.

This mine was a leader in the field of surface mining technology with the first in-pit primary crushing facility. This meant that ore was crushed by jaw crushers before taken out of the mine. They also used the first trolley-assist system for haul trucks coming out of the pit. Today the mine has secondary crushing facilities, concentrators and a refinery on site.

In 1982 a series of cavities with well-crystallised minerals were discovered, for example calcite crystals up to 15 cm on edge, silky mesolite crystals of up to 2cm long and octahedral magnetite crystals of 1-2 cm on the edge.

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