ernest henry crusher

ernest henry archives - international mining

ernest henry archives - international mining

Glencore, one of the worlds largest globally diversified natural resource companies, produces and markets a diverse range of metals and minerals, with its Australia copper and zinc operations including McArthur River Mine (Northern Territory), Lady Loretta Mine (Queensland), Mount Isa Mines (Queensland), Ernest Henry Mine (Queensland) and CSA Mine (New South Wales). Orica has an existing supply agreement with Glencores nickel and cobalt operations at Murrin Murrin, in Western Australia.

As part of the contract, Orica will deliver the full suite of explosives technology and blasting services across the Glencore copper and zinc operations in Australia, including supply of the fully wireless initiating system, WebGen, BlastIQ digital blast optimisation suite of products and smart explosives delivery system, Bulkmaster 7.

Orica Chief Executive, Alberto Calderon, said: Glencore is a key global diversified customer, and we are delighted to be partnering with them across their Australian copper and zinc operations, integrating our most advanced technologies and solutions to solve their more complex operational needs.

Glencores Ernest Henry mine in northwest Queensland was the first site in the world to trial and adopt our wireless explosives technology, WebGen. This deal shows Glencores confidence in our technology roadmap as well as aligning with their strategic vision for technology to deliver added value to their operations.

Mirabela Nickel, the mine owner, represented a pure-play nickel stock; Brazil, as a jurisdiction, was looked at favourably by investors; and the operation, itself, was one of the largest open-pit nickel sulphide mines in the world slated to produce 16,500 t/y of nickel sulphide in concentrate.

Gaining exposure to such a large, low grade asset is great when the underlying commodity price is tracking well, but, as has been shown time and again, it proves problematic when the price moves south.

The asset, in north-eastern Brazil, was eventually placed on care and maintenance in the March quarter of 2016 as Mirabela Nickel declared bankruptcy. This was the same year the nickel price dipped below $10,000/t.

Fortunately for the local community and personnel that had invested much hope in the development of the $1 billion-plus mine, Appian Capital Advisory more recently took the view that there was a way forward for Santa Rita.

Picking up on an emerging trend for clean and green nickel sulphide concentrate from the electric vehicle and stationary storage market, plus the ability to re-engineer the operation and make it a much more robust asset, the company carried out a six-month due diligence process on Santa Rita.

This process led Appian to refine its understanding of the presence of nickel sulphides within the deposit, as opposed to the assets total contained nickel. With this understanding in hand, a more defensive and low-cost mine plan was developed to see the asset through nickel price peaks and troughs.

Our resource now focuses on the estimation of nickel sulphide within the deposit and benefits from additional drilling weve undertaken post-acquisition, Adam Fisher, Principal, Appian Capital Advisory LLP, explained to IM. The mine design weve developed extracts the deposit more selectively and also moves less waste, resulting in the low cost performance weve been able to achieve to date.

In the first half of 2020, the company declared first quartile C1 cost performance of $3.17/lb ($6,989/t) nickel, net of by-products. This compares favourably with Mirabela Nickels $6.19/lb operating cost recorded in the September quarter of 2013.

Among the operating changes weve implemented are the use of a smaller, locally procured, equipment fleet of 40 t trucks (Santa Rita previously used Caterpillar 777 90 t and 785 137 t payload trucks), the use of shorter benches weve gone from 10 m down to, on average, 6 m and tighter blasting patterns, Fisher said.

The focus has gone beyond the near term, with more than 100,000 m of drilling executed in the underground resource area. The drilling was optimised for resource growth and classification confidence. The program was extremely successful and supported the declaration of the underground resource of 168 Mt at 0.59% NiS and 0.19% Cu. The 2020 drill programs continue to intersect similar widths and grades while stepping out from the declared resource, the company added.

The NI 43-101 technical report, released earlier this month, outlined a 34-year mine life for Santa Rita, with eight years of open-pit production, underpinned by proven and probable reserves of 50.6 Mt at 0.31% NiS, followed by 26 years of underground mining.

The last owners designed an open-pit mine with a 6:1 strip ratio and were planning to mine a lot deeper into the resource via open-pit methods, Fisher said. This was back in a very different nickel market when prices were greater than $10/Ib.

All we did was find the optimal transition to bulk methods at depth to understand that it only makes sense to mine this as an open pit over eight years at a strip ratio that comes down to, on average, 2.7:1.

Backing up this open-pit mine plan has been a 6.5 Mt/y plant, which, having started production in 2009, was completely refurbished and recommissioned in the second half of 2019 to align with the nickel sulphide recovery focus.

The plant consists of crushing, grinding, flotation, thickening and filtration unit operations to produce a saleable nickel sulphide concentrate. Flotation tailings are pumped to a tailings storage facility, while grinding is performed by a SAG mill, two ball mills and two pebble crushers. This is followed by a conditioning circuit and a flotation circuit, with the final concentrate thickened and pumped to storage tanks ready for filtration. Concentrate is filtered in a Larox (Metso Outotec) pressure filter. Following filtration, the final concentrate is trucked to the port of Ilhus where it is loaded onto ships for transport to market.

While the mine and plant are still ramping up, the open-pit operation is not far off from achieving the PEA estimates of being able to produce 20,000-25,000 t/y of contained nickel sulphide equivalent at a C1 cost of $2.97/Ib nickel, Fisher said.

Beyond this, the company is looking to leverage innovation to create one of the largest and most efficient sub-level cave (SLC) operations in the world able to produce more of the highly sought after nickel sulphide product Santa Rita is becoming known for.

When carrying out the due diligence on Santa Rita, we knew all along that there was some good, thick intersections underground, with the orebody getting thicker at depth and the nickel sulphide grade improving, Marcus Scholz, Head of Underground Mining at Appian Capital Advisory, told IM.

This was evident in the PEA, with underground mining inventory of 134.1 Mt grading 0.54% NiS and 0.17% Cu, comparing favourably in terms of grade with the proven and probable reserves of 50.6 Mt at 0.31% NiS and 0.11% Cu calculated for the eight-year open-pit operation.

Youre looking at a massive orebody with moderate grades, Scholz said. Factoring that in, the lowest cost methods will generate the better margins in this case. With SLC having come a long way in the last 20 years in terms of practices, philosophies and the ability to control dilution through effective planning and modelling, plus the suitable geometry of the Santa Rita orebody, it was a good fit.

Scholz was keen to point out that the company did not come to this conclusion on its own. It sought assistance from Power Geotechnical out of Australia, which has worked on other sub-level cave operations such as Carrapateena and Ernest Henry, when assessing its options.

Ernest Henry, operated by Glencore in Queensland, Australia, is a good analogue here. The Ernest Henry orebody is located at a similar depth below a pit and has a similar width and dip, but Santa Rita is about twice the size due to it being longer along strike, according to Scholz. It also comes with a similar 6 Mt/y profile.

The SLC mining layout in the PEA comprises 37 mining levels spaced at vertical intervals of 25 m. Each level is made up of parallel and evenly spaced drill drives from which production drilling and blasting occur. Once blasted, the mineralisation is loaded from the drill drives using LHDs and loaded into trucks for haulage to the surface during the initial ramp-up phase, and later to ore passes feeding an underground crushing station and conveying to surface via an inclined tunnel.

The underground operation will start with two years of waste development ahead of ore production, followed by ore truck haulage over a three-year period, Scholz outlined. After this, the operation will transition to underground conveyor haulage, ramping up to 6 Mt/y capacity over the next four years.

Over the life of the underground mine, the company plans to install two underground crushers, being fed with roughly equal amounts of ore. The first will serve the upper half of the deposit and the second crusher the lower half (circa-6 Mt/y each, staged as mining progresses deeper in the deposit).

Appian is looking to lease the 60 t trucks required for this stage of the operation, explaining that Atlantic Nickel will operate the 12 machines needed at the height of truck haulage, which is when mining rates hit the annualised 2.5 Mt/y mark.

The company assumed the use of automated LHDs, longhole drilling and jumbo development drilling in the PEA. This saw Epiroc, Caterpillar and Sandvik provide price inputs, with design layouts anticipating such equipment.

Scholz expanded on this for IM: We foresee that loaders going from the SLC drawpoints to the ore passes would be automated, meanwhile, at the collection level at the bottom of ore passes, we would probably have up to three large automated loaders that transfer material to the crusher.

The current study assumes the use of a diesel-powered load and haul (initially) fleet, though electric vehicles could provide upside in future studies and further reduce energy costs, equipment maintenance costs and ventilation power costs, an Appian spokesperson recently told IM.

Both tethered- and battery-powered machines will be looked at for specific applications within the mine, such as loading from drawpoints and feeding the underground crusher from the bottom of ore passes, the spokesperson explained.

While much of the industrys larger load and haul equipment has not yet made the commercial leap to battery power, the company is keen to pursue developments in the future as the technology became available, Scholz said.

The circularity of such a move will not be lost on Appian or Atlantic Nickel, knowing the nickel sulphide concentrate it will be offloading could end up in these battery-powered machines. In eight years, these end users will most likely be factoring such emissions-reducing technology into their raw material procurement choices.

Atlantic Nickel has released a preliminary economic assessment (PEA) on its Santa Rita nickel mine, in Brazil, that shows the potential for the company to become one of the largest sustainable nickel sulphide producers in the world.

This new NI 43-101 technical report outlines a 34-year mine life for Santa Rita, in Bahia, with eight years of open-pit production, underpinned by proven and probable reserves of 50.6 Mt at 0.31% NiS, and 26 years of underground mining.

The open-pit mine plan was prepared to prefeasibility study level and encompasses a large open pit and a nearby, much smaller satellite open pit along strike. Both pits will be mined with conventional mining equipment, and the plan will be executed in 10 phases, the company says.

The open pit is scheduled over a period of eight years, ending in 2028, with operations using standard methods of drilling and blasting, loading, and hauling. It would produce 20,000-25,000 t/y of contained nickel equivalent at a C1 cost of $2.97/lb Ni and an all-in sustaining cost (AISC) of $4.12/lb Ni, the company says.

The Santa Rita process plant, having started production in 2009, was completely refurbished and recommissioned in the second half of 2019 in line with the mine restart. The plant consists of crushing, grinding, flotation, thickening and filtration unit operations to produce a saleable nickel concentrate. Flotation tailings are pumped to a tailings storage facility, while grinding is performed by a SAG mill, two ball mills and two pebble crushers. This is followed by a conditioning circuit and a flotation circuit, with the final concentrate thickened and pumped to storage tanks ready for filtration. Concentrate is filtered in a Larox (Metso Outotec) pressure filter. Following filtration, the final concentrate is trucked to the port of Ilhus where it is loaded onto ships for transport to market.

The mineral resource estimate for the expansion case consists of 94.2 Mt of measured and indicated resources across open-pit and underground mining at average grades of 0.41% NiS, 0.14% Cu, 0.01% Co, 0.03 g/t Pd, 0.07 g/t Pt and 0.05 g/t Au, with 90.6 Mt of inferred resource at 0.54% NiS, 0.17% Cu, 0.02% Co, 0.04 g/t Pd, 0.09 g/t Pt and 0.06 g/t Au.

Sublevel Caving (SLC) was selected as the mining method for the underground portion of the deposit based on the amenable geometry of the deposit, and because productivity and cost advantages of SLC enable greater exploitation of the underground resource at greater margin than more selective mining methods, Atlantic Nickel said.

The geometry of the deposit and the location below a mined open pit are similar to the Ernest Henry SLC, which is successfully operated by Ernest Henry Mining (a subsidiary of Glencore) in Queensland, Australia, the company added.

The SLC mining method employs long-hole drilling and blasting techniques to extract mineralisation sequentially from the surface to the bottom of the deposit. The method does not require backfill and, therefore, relies on the overlying waste rock to cave and fill the mined void, the company explained. Caving of the overlying waste rock results in surface subsidence above and in the immediate vicinity of the underground deposit, but the subsidence will not interfere with open-pit mining since initial production from underground is planned to commence in 2028 when open-pit mining is completed.

Infrastructure capital and development of the underground project is planned to start at the beginning of 2026, with production from the underground ramping-up over a seven-year period until full production of 6.2 Mt/y is achieved.

The underground portion of the resource considered in the PEA plan consists of 43.5 Mt of indicated resources and 90.6 Mt of inferred resources. This resource was used to come up with a 40,000-45,000 t/y of contained nickel equivalent production profile for the underground operation over life of mine at a C1 cost of $2.17/lb Ni and an AISC of $3.92/lb Ni.

The SLC mining layout in the PEA comprises 37 mining levels spaced at vertical intervals of 25 m. Each level is made up of parallel and evenly spaced drill drives from which production drilling and blasting occur. Once blasted, the mineralisation is loaded from the drill drives using LHDs and loaded into trucks for haulage to the surface during the initial ramp-up phase, and later to ore passes feeding an underground crushing station and conveying to surface via an inclined tunnel.

The SLC method employs a top-down mining sequence that enables production to ramp-up quickly once the top of the underground deposit has been accessed, Atlantic Nickel says. The method also enables high production rates as the mining cycle is simplified by the standardisation of development and production and with no backfilling required.

While still early days in terms of the underground mines development plans, the company assumed the use of automated LHDs, longhole drilling and jumbo development drilling in the PEA, a spokesperson for Atlantic Nickel confirmed to IM. This saw Epiroc and Sandvik provide price inputs, with design layouts anticipating such equipment.

And, while the current study assumes the use of a diesel-powered fleet, battery-electric vehicles will also provide upside in future studies and further reduce energy costs, equipment maintenance costs and ventilation power costs, the spokesperson said.

Both tethered and battery will be look at for specific applications within the mine such as loading from drawpoints and feeding the underground crusher from the bottom of ore passes, the spokesperson said.

The flotation test work gave similar results to those obtained with open-pit material; hence, plant performance is not expected to be significantly different for underground material, the company said. Underground feed will be treated in Atlantic Nickels existing process plant with only minor modifications required, likely to the grinding circuit.

After completion of open pit mining, a new tailings storage facility would be required to store the additional 134 Mt of tailings to be produced from the underground mine over a period of 28 years. Like the existing tailings storage facility, raises will be constructed using a downstream method, the company said.

Total capital associated with the underground expansion amounts to $1.3 billion over the 34-year combined operation, with only $355 million of that being spent during the first five years of underground development commencing in 2026. The expansion is partially self-funding with cash flows generated from the open-pit mining operation, the company said.

Since the invention of the safety fuse by William Bickford in 1831, there has been three revolutions in blast initiation methods electric detonators (1930s), shock tube (1980s) and electronics (~2000s). Every new initiation method development has increased the safety, precision and possibilities of initiating blasts.

Still in its infancy with, as of August, more than 250 blasts fired using wireless initiation, the WebGen technology has already led to the development of several new mining techniques such as Temporary Rib Pillar (TRP), Temporary Uppers Retreat Pillar, Reverse Throw Retreat, Longitudinal Transverse Retreat and Pre-Loaded Retreat that would not be viable or possible without wireless blasting technology.

The system achieves wireless blasting through very low frequency magnetic induction (MI) signals communicated to the in-hole primer, with the special site-specific group ID, arm and firing codes embedded in the MI signals. The system eliminates the lead wires of conventional initiation systems, thereby also eliminating the hook-up process at the blastholes.

The operation works as follows: The i-kon plugin detonator plugs into the DRX, energising the device and initiating a self-test. After passing the self-test, the device can be encoded with the blast code and the delay timing. The booster is attached after encoding the device. At this stage the WebGen primer is ready to be placed into the blasthole.

The transmitter controller a magnetic induction system connected to an antenna sends the arming signal to the transmitter. Once the arming process is successful the firing window is presented to the blaster.

With the elimination of lead wires, it is possible to pre-charge a full stope (eg sub-level caving mining method) and fire every ring when required without sending personnel back to the dangerous brow area to connect lead lines, Orica says. Misfires related to damaged wires are eliminated and primers can be fired regardless of any dislocations of blasthole and/or charge.

The Ernest Henry mine, in north-eastern Australia, engaged Orica in 2016 to perform a demonstration of sub-level caving using WebGen. The mine wanted to reduce the time spent by personnel at the brow of the cave. With the use of WebGen they were successful in pre-loading the stope production rings and eliminating the need to return to the brow for hooking up.

At Newmont Goldcorps Musselwhite mine, productivity and ore recovery were the main drivers for looking into wireless blasting. Together with Orica, Musselwhite developed the TRP mining method where a temporary pillar is used to withhold backfill while the second mass blast (i-kon electronic detonators) of the stope is mucked out.

In March 2018, a team of Orica Technical Services Engineers commenced preparations and planning for the first wireless demonstration in Europe with the FQM Pyhsalmi mine, in Finland, the deepest mine in the continent.

At the time, the mine was scheduled to close in September 2019; most of the stopes had been mined out and the remaining stopes and pillars were becoming increasingly challenging to mine. Orica said: Pyhsalmi had developed a system to mine the stranded pillars, but this was incurring considerable time and costs. Pyhsalmi mine acknowledged that WebGen 100 could be a solution for the problems in retrieving remaining ore in difficult areas.

As a first stop, the Orica team of blasting specialists had to assess if the WebGen system would successfully function in Pyhsalmi mine. Before firing the WebGen shot it was important to investigate if the system would work in the mine and what the maximum signal reach would be for both the quad loop and cable loop antenna, the company said.

Pyhsalmi experiences occasional sulphur dust explosions and, therefore, personnel are not allowed to be underground while blasting, Orica said. As a result, blasting takes place at the end of the shift after the shift explosives supervisor checks everyone has vacated the mine.

In September 2018, the EMEA WebGen team returned to Pyhsalmi mine for the first wireless blast in Europe. The final three rings of stope 18b10-11 on Level 1,175 were selected for the demonstration blast.

For one of the wireless blasts, a stope would not be accessible after the first blast, but, as the stope could be pre-loaded with wireless detonators, the mine could blast and produce 4,000 t of extra ore that otherwise would have been sterilised.

Katja Sahala, Mine Planning Engineer, FQM Pyhsalmi mine, said she saw the WebGen wireless system as helping operations in several applications such as when ore needs to be left behind to support pillars, or where there is weak rock, or fill and selective mining is required.

She said: In uphole charging, you need to work close or even below an open face during drilling and blasting. If its possible to drill and charge an entire stope before the first hole is fired, then safety will surely be improved.

Orica said wireless blasting is a new and exciting technology that eliminates the use of cumbersome and complex wiring hook-ups while having the accuracy of an electronic detonator. It has already enabled safer work methods and mining techniques that increase recovery, productivity and efficiency, according to the company.

It concluded: Many technical and regulatory challenges will be faced by wireless blasting, but it is a fundamental step in the automation of the explosives charging and blasting process. With the first WebGen blasts at FQM Pyhsalmi mine, wireless blasting is no longer a dream in Europe, but a reality.

glencore begins shaft hoisting from ernest henry underground | e & mj

glencore begins shaft hoisting from ernest henry underground | e & mj

Glencore reported on June 25 that the new, 1-km-deep hoisting shaft at its Ernest Henry mine near Cloncurry in northwest Queens-land, Australia, had begun operations. The shaft is a key element of an A$589 million project to transition the Ernest Henry mine from open-pit to underground production. Mine production will ramp up from 3 million to 6 million mt/y in 2015, and production of metal in concentrate will similarly double to 50,000 metric tons per year (mt/y) of copper and 70,000 oz/y of gold over an extended mine life to 2026.

The Ernest Henry underground project began in December 2009 and has included more than 50 km of underground development accessed by a 6-km decline; construction of associated infrastructure, including an underground primary crusher and 1.2 km of below-surface and overland conveyors to transport ore to and from the hoisting system; installation of a 75-m-high permanent headframe to house the hoisting system, which has capacity to lift around 1,000 mt/h; and reconfiguring the concentrator to align with the underground production rate.

The underground mine utilizes an innovative sublevel caving mining method and is currently operating across four production levels. Ore has been trucked to surface via the decline since December 2011, and the decline will continue to be used as the main access point for the underground workforce over the life of the mine.

Glencore COO for copper assets in North Queensland Mike Westerman said, Our assets in Mount Isa and at Ernest Henry accounted for around 14% of Glencores global copper production in 2013. This investment in Ernest Henry has effectively added 14 years to the life of the mine to 2026.

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