Tag Archives: zinc

MMG, Barminco trialling Sandvik autonomous LHD at Dugald River

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MMG and Barminco are trialling an automated LHD at the Dugald River mine, in Queensland, Australia, as both miner and contractor look to further boost production at the zinc-lead operation.

While still early days, Barminco (part of the Perenti Group) has a fully autonomous Sandvik LH621i LHD running at the mine, having introduced the loader to increase output.

Sandvik says the AutoMine®-ready LH621i is an intelligent 21 t loader designed for rapid mine development and large scale underground mine production.

“With superior hydraulic power for fast bucket filling and drivetrain power for high ramp speed, the Sandvik LH621i is designed to quickly clear tunnel headings for rapid advance rates,” the OEM added.

MMG’s Dugald River produced 35,505 t of zinc concentrate and 4,277 t of lead concentrate during the March quarter of 2020. While both numbers were lower than the same period of 2019 and the December quarter that preceded it due to lower grades, mining and milling volumes of 462,570 t and 443,378 t, respectively, were both in line with plan.

In this same results release, MMG said of the Dugald River operations: “After an aggressive and successful ramp up during 2019, work in 2020 will continue to focus on opening up new operating areas, to ensure a steady feed of ore to the mill.

“The optimisation of recoveries will be a major area of focus in the processing plant. This work will be key in ensuring Dugald River remains on track to deliver annual mine capacity of 2 Mt and targeted zinc-equivalent production in excess of 200,000 t per annum, by 2022.”

The mine, which achieved commercial production in May 2018, is expected to produce 170,000-180,000 t/y of zinc concentrate in 2020.

Sotkamo Silver chases processing efficiencies with Outotec-TOMRA XRT solution

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Sotkamo Silver is looking to reduce the amount of material it grinds and floats at its silver operation in Finland through the introduction of X-ray Transmission (XRT) ore sorting technology.

The company said it began pilot testing of the XRT machine in May after the unit was supplied and successfully commissioned at the mine by Outotec and TOMRA. Outotec and TOMRA have been cooperating on the supply of Outotec-branded sorting solutions for the mining and metallurgical industry since 2014.

Sotkamo’s trial pilot testing builds on previous test work at TOMRA’s testing facilities in Germany.

Previous XRT ore sorting test work carried out by TOMRA on 2,200 kg of Sotkamo samples showed the silver content from low-grade ore increasing some 1.9 x to 116 g/t Ag, while the average silver content in ore rose 1.43 x to 195 g/t Ag. In addition to this, about 60% of the rock previously classified as low-grade ore was removed as gangue with the testing, with some 43% of rock reporting as gangue from the average grade ore samples.

Following this work, back in 2018, Sotkamo Silver said it was looking to install an Outotec-TOMRA XRT ore sorter in the process flowsheet after two-stage crushing (jaw and cone crushers) had taken place and the rock was some 30-70 mm in size.

In the update today, Sotkamo Silver said the XRT technology can scan every feed particle to identify the relative atomic density differences within particles and then separate desired high-grade particles from the barren material pneumatically.

It said sorting of marginal ore would be carried out after primary crushing and it was expected to reduce roughly 50% of non-ore material going into the grinding and flotation process.

“This improves significantly the energy efficiency as less material is grinded, and also material efficiency as marginal ore can be exploited and processed to mill feed,” the company said, adding that leftover barren material would be used as rock-fill in the underground mine.

During the first three months of 2020, around 129,000 t of ore was processed at the silver mine, yielding some 391,000 oz of silver, 462 t of lead, 958 t of zinc and 998 oz of gold in the concentrates.

Orion settles on SAG milling and water treatment at Prieska Cu-Zn project

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Two significant engineering changes have had a positive impact on the expected returns from Orion Minerals’ Prieska copper-zinc project in the Northern Cape Province of South Africa.

Issuing an updated bankable feasibility study (BFS) for a proposed new 2.4 Mt/y copper and zinc mining operation earlier this week, the company said there had been “numerous improvements” on the previous study completed in June 2019.

This included a 43% increase in post-tax undiscounted free cash flows from the project to A$1.2 billion ($798 million); a 36% increase in after-tax net present value (8% discount rate) to A$552 million; and a five-month reduction in the capital payback period to 2.4 years.

In the plant, the major changes include the use of SAG milling, and removal of secondary crushing, screening and rock conveyors.

The use of a SAG and ball milling circuit followed by differential flotation removes the need for multiple stages of crushing – which was included in the previous study.

The new plan envisages a high steel charged SAG mill operating in an open circuit with a secondary ball mill operated in a closed circuit with a classification cyclone cluster. The SAG mill trommel screen oversize feeds a pebble crushing circuit which returns crushed product to the SAG mill feed conveyor, the company said.

The milling circuit, meanwhile, is fed with (F100) 250 mm primary crushed material from the primary stockpile at a throughput rate of 300 t/h and produces a product size of 70% passing 75 μm, which is fed to the differential flotation circuit.

In a presentation, Orion stated that the processing plant costs from the 2019 study to the latest BFS had dropped 16% to A$91 million.

The next big change was a different de-watering philosophy of the old workings of Prieska, with the BFS including a new water treatment route. This resulted in a 30% decrease in the shaft dewatering timeline, it said.

The Hutchings Shaft and underground workings at Prieska are currently filled with water to a depth of 310 m below surface and contain a volume of 8.6 Mcu.m of water.

Dewatering of the workings via a pumping system to be installed in the Hutchings Shaft is now planned, with water being pumped into a 1 Mcu.m volume dewatering dam on surface, from where mechanical evaporators and a reverse osmosis water treatment plant will be used to dispose of and treat the water for discharge into the environment.

The use of water treatment supplements mechanical evaporation, which allows the pumping schedule to be accelerated by four months, Orion said. “Furthermore, the Department of Human Settlements, Water and Sanitation stipulated as part of the IWUL (Repli Integrated Water Use Licence) application process that provision be made for a portion of the dewatered volume to be made available for social, commercial or agricultural use in the locality.”

Forced evaporation is planned to be used as the primary means to dispose of the water with the water treatment plant (WTP) as the secondary means to treat and then discharge treated water into the environment as irrigation water.

Forced evaporation requires the use of a large evaporation dam, according to Orion, which impacts environmental considerations when compared with the small footprint required by the WTP.

“This is mitigated through the early construction of the tailings storage facility (TSF) which serves a dual purpose for early project phase dewatering and later as a TSF during the operational life of the mine,” the company said.

These actions, in addition to prioritising the extraction of higher grade (and confidence) mineral resources earlier in the mine schedule, helped significantly improve the project return economics, according to Orion.

While the changes also came with a 9% increase in peak funding requirements to A$413 million to cater for the operational improvements, it would also see 20% more payable copper produced – 226,000 t – and 17% more payable zinc produced – 680,000 t – over the 12-year mine life.

Orion’s Managing Director and CEO, Errol Smart, said: “With the Prieska BFS update now complete, the development of the Prieska project is ideally positioned to play a vital role in the local economic recovery plan for the Northern Cape region.

“The project’s low exposure to imported materials and foreign labour reduces construction challenges as the world overcomes and recovers from COVID-19.”

Smart added that the company was targeting a production start-up in 2024 as market conditions permitted.

Sandvik trialling Stage V engine technology at Boliden’s Tara mine

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Sandvik is continuing its sustainability drive, announcing that it is trialling its first Stage V compliant underground truck at the Boliden-owned Tara zinc mine in Ireland.

The company, in December 2019, launched its first Stage V compliant underground LHDs for hard-rock mining applications following extensive testing. Back then, it said its newest intelligent loaders, the Sandvik LH517i and Sandvik LH621i, would receive the Stage V treatment in early 2020.

Now, Sandvik’s flagship truck, the TH663i, equipped with brand new Stage V Volvo Penta engine technology, is undergoing an extensive field trial period at Tara, allowing the company to obtain first-hand customer feedback on its technical and operational performance. Sandvik said this was “an integral part of Sandvik’s way of working and customer-focused mindset”.

The Stage V engine in the 63 t truck is expected to deliver lower emissions, contributing to reduced mine ventilation rates.

“Designed to fit seamlessly together with the truck and to perform specifically in underground use, the engine system includes built-in fire prevention solutions, increased wiring protection with shrink mesh wiring harness and electric hardware that is specifically designed for demanding conditions, with corrosion, heat and water resistance,” it said. “The new Stage V, requiring ultra-low sulphur fuel and low-ash engine oil to operate, will be an optional engine for the TH663i.”

To reduce particle emissions in the lower Stages/Tiers, standard engines on both the TH663i and TH551i trucks can be equipped with a diesel particulate filter (DPF), according to Sandvik. The company explained: “Based on studies conducted, the optional sintered metal DPF reduces particle mass by approximately 99%. From a reliability and maintenance viewpoint, the DPF is well protected but still designed for easy cleaning to reduce downtime and operating costs. The DPF is also available as retrofit kit.”

Pia Sundberg, Product Line Manager for Trucks at Sandvik Mining and Rock Technology, says thorough field tests are valuable to both the OEM and customer: “We want to allow enough time for sufficient testing of new technology, since it is of benefit to both sides.

“Possible hiccups that can often occur when developing something new are identified prior to the product being fully commercialised, which enables us to serve our customers better in the long run.

“Based on the feedback that we receive, we are still able to do some modifications if necessary and thereby make sure that the TH663i meets expectations when it is released to the market with the latest engine technology at a later stage. Of course, there is also some additional new technology on the test truck that we are testing at the same time.”

The TH663i also benefits from the recent improvements in Sandvik’s AutoMine® offering, as AutoMine for Trucks now enables autonomous truck haulage not only underground but also on the surface.

Sandvik said interesting glimpses into the company’s future truck offering have also been seen in Australia, where the Artisan Z50 battery truck from Sandvik carried out an extensive tour in early 2020 and gathered customer feedback for the new upcoming battery generation.

The company has also recently deployed a Z50 into Barrick Gold’s Turquoise Ridge underground gold mine, in Nevada.

Mexico miners to suspend operations for April following government decree

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Mexico has become the latest country to enforce a suspension of non-essential activities in response to the outbreak of the COVID-19 pandemic, with its Ministry of Health ordering a temporary halt of activities until April 30 in order to slow the virus spread.

Mexico is the world’s largest silver producer, having produced 6,300 t of the precious metal in 2019, according to the US Geological Survey. This was an increase of 180 t, year-on-year. It is also hosts major copper and zinc mines operated by Grupo Mexico and Southern Copper, and produces a significant amount of gold.

It joins the likes of Peru, Quebec and South Africa in declaring suspensions of all non-essential activities in order to curb the spread of the virus.

Among the miners with operations in the country to have already reacted to the Mexico Ministry of Health’s announcement was Newmont, Pan American Silver, Sierra Metals and Argonaut Gold.

Newmont, which operates the Peñasquito mine in the state of Zacatecas, said it was taking steps towards a safe and orderly ramp down of operations at the asset.

“At this time, mining has not been deemed an essential activity under the decree and the company is engaging with the government to understand the intended impacts of the decree on operations,” it said.

“Peñasquito will work closely with local governments, neighbouring communities, employees, unions and contractors to ensure a safe and orderly ramp down that complies with the federal government’s directives.”

Tom Palmer, President and Chief Executive Officer of Newmont, said the company intended to comply with Mexico’s latest directive, while engaging with the government to gain further clarity regarding “important activities that may continue at the mine”.

In the meantime, the company would ensure Peñasquito, which is the largest gold mine, second largest silver mine and one of the largest producers of zinc and lead in Mexico, remains well-positioned to safely and efficiently ramp up operations in a timely manner once the government’s directive is lifted, Palmer added. This includes maintaining critical safety, environmental management, infrastructure maintenance and security activities, while continuing to provide essential community support.

Pan American Silver, which operates the La Colorada (Zacatecas, pictured) and Dolores (Chihuahua) operations in Mexico, said it would expand its initiative of reducing the number of people on site to increase physical distancing, to bring the mines into compliance with the executive order.

It is continuing to conduct care and maintenance at the suspended operations to sustain strict safety and environmental systems, and to ensure operational readiness when the government restrictions are lifted and Pan American determines it is safe to resume operations, it added.

La Colorada produced 8.2 Moz of silver in 2019, while Dolores’ output came in at 5.1 Moz.

As a result of this declaration, Sierra Metals said it will only maintain an essential services crew at its Bolivar mine site until April 30, and the Cusi mine site will be placed into care and maintenance during this period. “The company anticipates resuming normal production levels at the mines after this period,” it said.

Bolivar, an underground mine with a 3,600 t/d processing capacity, had previously been expected to produce 16,402- 18,225 t of copper-equivalent in 2020, while the Cusi underground mine was down to produce 1,732-2,126 oz of silver.

Sierra Metals added: “Production can recommence to normal levels very quickly after April 30, and the company has some operating flexibility at Bolivar to run the ore processing mill at higher levels, which should help recover lost ore tonnages from this suspension.”

Argonaut Gold, which is looking to merge with Alio Gold – a transaction that will see it increase its Mexico exposure – said it was working towards an orderly suspension of mining, crushing and stacking activities at its El Castillo gold-silver open-pit mine in Durango, and its La Colorada open-pit operation in Sonora. These assets produced 131,277 gold-equivalent ounces and 55,338 gold-equivalent ounces, respectively, in 2019.

The company added: “Given that Argonaut operates heap leach mines, the company expects metal production and metal sales will continue during the temporary suspension of mining activities.”

Robit drilling consumables in transit to Norilsk Nickel

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Robit says it has signed a contract to supply drilling tools to Norilsk Nickel, in Norilsk, Russia, with the deliveries expected to take place during April and May.

Norilsk is in Krasnoyarsk Krai, Russia, and located above the Arctic Circle. Since there are no roadway or railway connections, all freight is delivered by cargo ship via the Arctic Ocean to the Port of Dudinka, in Murmansk, or by air. The Robit drilling consumables are to be delivered by sea, Robit said.

Norilsk Nickel is one of Russia’s leading metals and mining company, a manufacturer of palladium and refined nickel, and one of the biggest platinum and copper producers in the world. The company also produces cobalt, rhodium, silver, gold, iridium, ruthenium, selenium, tellurium, and sulphur.

Robit, meanwhile, provides drilling consumables for applications in mining, construction and contracting, tunnelling, and well drilling. It has two product and service ranges: top hammer and down-the-hole.

Last month, the company signed a two-year contract to supply drilling tools to Al Masane Al Kobra Mining Co, in Saudi Arabia, for underground jumbo rigs at its Al Masane copper-zinc mine. The tools are to be supplied by Robit’s distributor, Bin Harkhil.

In February, Robit delivered its first consignment of rods for underground drilling to Ma’aden’s Al Amar underground gold-copper-zinc mine, in Saudi Arabia.

AGQ Labs to keep environmental tabs on Glencore’s Contonga polymetallic mine

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AGQ Labs’ mining division has been awarded a contract to carry out the environmental monitoring of the quality of soil, water, plant and hydrobiological tissue at Glencore’s Contonga polymetallic mine, in Peru.

The Contonga mine, in Ancash, is owned by Glencore subsidiary Compañía Minera Los Quenuales. It is a polymetallic underground zinc, lead, copper and silver mine with more than 100 years of operating history, according to AGQ Labs. Glencore acquired the asset from Nyrstar back in September 2017.

The mining company, as part of its environmental commitment at the mine, performs environmental monitoring of its components to determine their chemical stability and the potential for acid mine generation, as well as their characterisation through complementary studies, AGQ Labs said.

AGQ Labs Mining will provide the sampling service and technical analytical support through a specialised service for the characterisation of soils, waters and plant tissue. This uses selective analytical techniques for the characterisation of the matrices under study.

For this, AGQ Labs uses a set of tests to define the quality of the soils under study through fertility tests and characterisation of the profiles.

Mobilisation of the different analytes under study are also characterised through leaching tests such as methodologies proposed by Tessier and the Flask Extraction Test. The characterisation of its acid generation capacity with ABA methodologies and mineralogy analysis is carried out with Thin Sheet Microscopy.

AGQ Labs said: “The characterisation works are complemented by the taxonomic classification of the most representative flora and the study of the waters through laboratory analyses of physicochemical and hydrobiological parameters.”

XRT ore sorting shows promise at Vendetta Mining’s Pegmont project

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Following positive X-ray Transmission (XRT) ore sorting test work on the Pegmont asset, in Queensland, Australia, Vendetta Mining is looking to apply this technology in its next mining study at the lead-zinc project.

The test work, conducted at TOMRA’s testing facility in Sydney, Australia, concluded that the XRT sorters could distinguish between high-density/high-grade feed and lower-density waste material at Pegmont, the company said.

Vendetta said: “At Pegmont, the potential advantages of XRT material sorters is that they could allow plant feed material to be screened prior to grinding and flotation, removing lower density external dilution (waste) and lower-grade internal dilution (material below cutoff).”

Potential capital cost savings occur through the reduced mill throughput while potential operating costs savings occur through reduced water and reagent usage, less pumped tails and lower energy requirements, it said.

The test work envisages that sorted waste product would be ejected and stacked for dry disposal (dry stack tailings).

Vendetta said: “Flotation recovery often improves with increasing head grade. Such a relationship exists in the metallurgical test work performed at Pegmont to date. The higher head grades obtained from the ore sorted product are anticipated to result in enhanced flotation recovery.”

The testing involved material from two drill hole intersections from Zone 5 and one from Zone 2 at Pegmont. The sulphide intersections were selected in order to test different lead to zinc ratios (Zone 5 vs Zone 2) and internal grade distributions, it said. All samples included diluting quartzite material from the hangingwall and footwall.

The conclusions of the XRT ore sorting preliminary test work on the three drill intervals are it can successfully remove the external dilution from the samples; and successfully remove internal diluting material from within the higher-grade intervals.

The total mass tested amounted to 139.2 kg, with the mass pull (weight % of feed recovered) ranging from 44.3% to 70.6% (a weighted average of 62.3%).

The lead grade improved from 18% to 88%, a weighted average of 42%; zinc grade improved from 21% to 72%, a weighted average of 38%; lead recoveries ranged from 83.2% to 90.2%, a weighted average of 88.5%; and zinc recoveries ranged from 76.4% to 92.2%, a weighted average of 85.9%.

Vendetta said that while these results were highly encouraging, they are preliminary. “In order to apply material sorting results in an updated preliminary economic assessment (PEA) study, pilot scale test work is necessary,” the company said.

TOMRA recommends 600 kg of material is required for each ore type at Pegmont. Vendetta plans to pursue this test work and expects these samples will be obtained from the next drilling program. Samples will be obtained from Zone 1 transition, Zone 2-3 sulphide and Zone 5 sulphide.

Michael Williams, President and CEO, said: “At Pegmont, the XRT sorter can clearly differentiate between high density/high grade feed from lower density waste material at Pegmont. We are excited by the prospects of advancing to pilot scale test work and applying this commercially available technology to the next mining study.”

The existing Pegmont PEA contemplated a production rate of 1.1 Mt/y, which corresponds to two TOMRA COM XTR 1200 – generation one ore sorters, Vendetta noted.

GR Engineering awarded with Abra EPC contract

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GR Engineering Services has been awarded a conditional engineering, procurement and construction (EPC) contract to deliver a 1.2 Mt/y lead sulphide flotation process plant and ancillary infrastructure for Galena Mining’s Abra Base Metals project in Western Australia.

The award, worth some A$74 million ($50 million), follows work carried out by the ASX-listed engineering company on the feasibility study and at the preliminary design stage of Abra.

The work will be undertaken on a guaranteed maximum price basis, according to GR Engineering, which confirmed that the contract remained subject to GR Engineering being issued with a full notice to proceed. This is dependent on Abra Mining Pty, Galena’s operating subsidiary, achieving financial close on its proposed project financing facilities. Galena, which owns 86.16% of the project through Abra, has said it will require A$170 million of pre-development capex to get the mine up and running.

GR Engineering has already commenced early engineering works up to an agreed capped amount, it said.

Geoff Jones, Managing Director of GR Engineering, said: “We are pleased to have been awarded the contract for the delivery of the Abra Base Metals project, which has followed GR Engineering’s involvement to date in the project’s feasibility study and preliminary design work.”

Galena completed a definitive feasibility study on Abra last year for development of a mine and processing facility with a 16-year life producing a high-value, high-grade lead-silver concentrate containing around 95,000 t/y of lead and 805,000 oz/y of silver after ramp-up.

Earlier this month, the construction of the Abra box cut commenced (pictured).

Heron starts processing underground ore at Woodlawn zinc-copper mine

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Heron Resources says it has started crushing and processing the first underground ore from the high-grade G2 lens at its Woodlawn zinc-copper mine in New South Wales, Australia.

The ore from the G2 lens was mined 135 m below surface and was discovered during Heron’s on-mine exploration drilling programs during 2017.

Since the commencement of the underground campaign, around 10,000 t of G2 stoped ore was delivered to the plant at 3.9% Zn, 1.3% Pb, 0.3% Cu, 31 g/t Ag and 0.6 g/t Au. This was in addition to 6,000 t of G “hangingwall” ore at 4.7% Zn, 2.6% Pb, 0.7% Cu, 268 g/t Ag, 2 g/t Au; plus 2,000 t of high-grade development ore at 7.3% Zn, 3.7% Pb, 4.9% Cu, 30 g/t Ag and 0.9 g/t Au.

The first stages of commissioning were completed using tailings reclaim feed material, with some preliminary commissioning of the crushing and ball mill plant during August and September.

Heron says the plant is now receiving run of mine underground ore and will complete a campaign solely on this feed source. This will facilitate the next phase of commissioning for the crusher and ball mill and marks the start of the ramp-up phase for this part of the circuit.

In steady state, the plant will alternate between campaigns of tailings reclaim feed and underground ore.

With stope ore now being mined and processed, paste fill activities have also been progressed, with the final commissioning of the paste plant and a number of placements underground of paste fill now complete.

Heron’s Chairman, Stephen Dennis, said: “The first ore mined and now processed from the G2 lens is a significant achievement for the operations at Woodlawn. The high-grade G2 lens was planned to be the first underground ore through the plant and will generate early revenue in these first stages of underground mining.”

The forecast development includes access to the G3 (north) area that contains stopes that are in an independent sequence from the current G2, G3 (south) and GH stoping area.

Processing of reclaimed tailings is ongoing and underground ore campaigns are being scheduled in line with the current production plan. Ramp-up of the processing plant continues and the plant is scheduled to achieve rated capacity on a sustainable basis from mid-2020.