Tag Archives: Silver

Orla Mining on course for first gold in 2021 at Camino Rojo Oxide project

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The publication of the updated feasibility study on Orla Mining’s Camino Rojo Oxide Gold asset in Zacatecas, Mexico, has come with a 54% increase in contained gold reserves and a 3.5-year extension to the mine life of the in-construction project.

The new reserve estimate at Camino Rojo includes a proven and probable total of 67.4 Mt at 0.73 g/t Au and 14.5 g/t Ag, for total mineral reserves of 1.59 Moz of gold and 31.5 Moz of silver.

The updated study outlined open-pit mining of 67.4 Mt of oxide and transitional ore at a rate of 18,000 t/d. Ore from the pit will be crushed to 80% passing 28 mm, conveyor stacked onto a heap leach pad and leached using a low concentration sodium cyanide solution. Pregnant solution from the heap leach will be processed in a Merrill-Crowe recovery plant where gold and silver will be precipitated and doré will be produced. The site’s proximity to infrastructure, low stripping ratio, compact footprint and flat pad location all contribute to the project’s simplicity and low estimated all-in-sustaining costs of $543/oz of gold, the company said.

An after-tax net present value (5% discount) of $452 million was calculated by the study team led by Kappes Cassiday and Associates and supported by Independent Mining Consultants, Resource Geosciences Inc, John Ward Groundwater Consultant, Barranca Group, Piteau Associates Engineering and HydroGeoLogica Inc.

The main notable physical changes from the 2019 feasibility study are an increase in the size of the open pit, heap leach pad, and mine waste dump because of a layback agreement with the adjacent Fresnillo mine, all of which were anticipated in the initial design. While all material to be mined on the Fresnillo concession has been classified as waste in the latest study, Orla sees opportunities to further expand the reserve and resource base following further work on material in this area.

Jason Simpson, President and Chief Executive Officer of Orla, said: “The updated feasibility study for the Camino Rojo Oxide project demonstrates an increase in recovered gold, mine life, and cash flows.

“An already excellent project has been improved due to the hard work of the entire Orla team and I thank them for their efforts. We are pleased to announce this important enhancement and we will continue to optimise this asset as we move through construction and into production.”

Detailed engineering of the project described in the 2019 feasibility study is over 90% complete and procurement is 85% complete, with the start of earthworks announced on November 26, 2020. Since that time, 230 ha have been cleared for construction activities with over 20,000 cu.m of topsoil being removed and stockpiled. Equipment deliveries to site commenced in December, with a total of $78 million of the total project capital committed through purchase orders and contracts.

Orla says the mining contract is being finalised and expected to be in place early in the March quarter, with first gold production planned for late 2021.

SilverCrest adds process plant EPC remit to Ausenco’s Las Chispas FS work

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SilverCrest Metals is racing ahead with securing one of the key contracts for its Las Chispas project in Mexico, with one of its Mexican subsidiaries entering into a fixed price engineering, procurement and construction (EPC) contract with Ausenco Engineering Canada and one of its affiliates ahead of the publication of a feasibility study on the silver-gold project.

While the study is still pending finalisation by Ausenco, with announcement of results targeted for late January 2021, SilverCrest says it is confident entering into the process plant agreement based on the substantial feasibility information currently available.

At the same time, the company entered into a $120 million project financing facility with an affiliate of RK Mine Finance for funding the Las Chispas build.

The lump sum turnkey price of $76.5 million for the EPC contract will include construction of a 1,250 t/d process plant at Las Chispas, with execution of Ausenco’s scope of work to begin in February 2021, and commissioning of the process plant targeted for the June quarter of 2022. The process plant production ramp-up is expected to start in the September quarter of that year.

The construction execution plan includes stringent COVID-19 protocols including the use of a confined single room occupancy camp designed to limit the potential for a virus outbreak at the site and in the local communities, SilverCrest says.

Ausenco is in the throes of completing the Las Chispas feasibility study and progressing detailed engineering and the construction management plan. Detailed engineering is progressing well at around 60% completion, according to SilverCrest, and procurement of long lead items started in the final quarter of 2020.

“Advancing these programs in parallel has allowed Ausenco to develop comprehensive capital and operating cost estimates for Las Chispas while progressing detailed engineering beyond what is customary at a feasibility study level,” SilverCrest said.

“The disruption caused by the COVID-19 pandemic also allowed SilverCrest to initiate an early works program tailored to further reduce project execution risks.”

This early works program included the earthworks package, the water pumping system and the first phase of the construction camp. The advancement of the program, coupled with the fixed price nature of the EPC contract, reduces many common construction and market-related risks, the company said.

Beyond the tasks included in the EPC contract, the remaining initial capital costs anticipated for Las Chispas construction will include development costs of the underground mine; owner’s site costs; on-site infrastructure including Phase 2 of the confined construction camp, a bridge and the filtered (dry stack) tailings system facility; a new 33 kV, 49 km long powerline; and an analytical laboratory located in the community.

Pierre Beaudoin, COO of SilverCrest, said: “We are pleased to be working with Ausenco, a well-known and respected engineering firm with substantial global experience in designing, constructing, and commissioning precious metal process facilities. We have been working closely with Ausenco to complete the EPC contract and the feasibility study in close succession. We are confident that their intimate knowledge of the project will benefit the successful construction and commissioning of Las Chispas.”

A February 2019 preliminary economic assessment on Las Chispas outlined a 1,250 t/d production rate with an initial mine life of 8.5 years. This resulted in average annual production of 5.38 Moz of silver and 55,700 oz of gold.

McEwen Mining progresses gold-silver heap leach plan at Fenix

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McEwen Mining looks to have found a way to prolong its operations at the El Gallo Complex in Sinaloa, Mexico, with the feasibility study for its 100%-owned Fenix project highlighting a 9.5-year operational blueprint.

Using gold and silver prices of $1,500/oz and $17/oz, McEwen has estimated an operation able to produce 26,000 oz of gold production in phase one (years one to six) and 4.2 Moz of silver-equivalent in phase two (years seven to nine-and-a-half).

Phase one comes with an initial capital bill of $42 million and an all-in sustaining cost (AISC) estimate of $1,042/oz of gold. Phase two would require a $24 million incremental capital injection in year six, with the AISC calculated at $14.28/oz of silver-equivalent.

The company’s El Gallo mine (pictured) produced 240,000 oz of gold and 125,000 oz of silver from 2012-2017, yet, due to the transition to deeper sulphide mineralisation not amenable to heap leaching, mining and crushing activities ceased in the June quarter of 2018.

While residual heap leaching is set to continue to produce gold for several years, the company has been working on a new project for the El Gallo Complex, which is where Fenix comes in.

The Fenix 2018 preliminary economic assessment evaluated the potential extension of production in the complex, based on a two-phased transformation of the processing from the El Gallo mine, innovative in-pit tailings disposal and sourcing from several deposits.

The latest feasibility study has run with that plan, with the critical path environmental permits in hand for the first phase of production, according to Rob McEwen, Chairman and Chief Owner of McEwen Mining.

“Our next steps will involve detailed engineering, assessment of procurement options and the evaluation of financing alternatives,” Rob McEwen said.

He added: “The project will incorporate an environmentally progressive method of tailings management, using in-pit storage that creates multiple benefits, most importantly a secure containment of tailings, enabling better reclamation results.”

VanGold adds El Cubo mine and mill to El Pinguico precious metals mix

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VanGold Mining has signed a binding agreement with Endeavour Silver to acquire the El Cubo mine and mill complex in Mexico, accelerating the company’s transition from development to production at its nearby El Pinguico silver-gold project.

With a rated capacity of 1,500 t/d, the El Cubo complex is made up of two operating underground silver-gold mines and a flotation plant. It employed over 350 people and engaged over 200 contractors until Endeavour suspended operations at the end of November 2019.

For the year ended December 31, 2018, Endeavour produced a total of 4.58 Moz of silver-equivalent at the complex at an all-in sustaining cost of $8.86/oz.

Currently, the El Cubo mine, plant and tailings facilities are on short term care and maintenance. VanGold intends to re-start the mill at around 750 t/d using mineralised material from its surface and underground stockpiles at the El Pinguico project as a significant portion of its estimated throughput for the first 36 months of operation. Endeavour Silver states it has measured and indicated resources of 236,000 oz of silver equivalent at El Cubo.

VanGold Chairman and CEO, James Anderson, said: “After working well with the Endeavour team during our 1,000 t bulk sample in June 2020, it became clear that El Cubo would be the perfect production fit for VanGold.

“The availability of mineralised material from El Pinguico’s surface stockpile, El Pinguico’s underground stockpile, El Pinguico’s remaining high-grade historical stopes and pillars, as well as El Cubo’s historical resources, gives us great flexibility in deciding where to source material for the mill, and how to sequence that throughput.”

El Pinguico is a high-grade gold and silver deposit that was mined from the early 1890s until 1913. VanGold has recently gained access to some of the historical underground shafts and has drilling campaigns planned to explore these areas.

AngloGold Ashanti confirms caving plans in Colombia

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The Massmin 2020 crowd got a glimpse of just what will be required to build Colombia’s first underground caving mine during a presentation from AngloGold Ashanti’s Lammie Nienaber this week.

Nienaber, Manager of Geotechnical Engineering for the miner and the presenter of the ‘Building Colombia’s first caving mine’ paper authored by himself, AngloGold Ashanti Australia’s A McCaule and Caveman Consulting’s G Dunstan, went into some detail about how the company would extract the circa-8.7 Moz of gold equivalent from the deposit.

The Nuevo Chaquiro deposit is part of the Minera de Cobre Quebradona (MCQ) project, which is in the southwest of Antioquia, Colombia, around 104 km southwest of Medellin.

A feasibility study on MCQ is expected soon, but the 2019 prefeasibility study outlined a circa-$1 billion sublevel caving (SLC) project able to generate an internal rate of return of 15%. Using the SLC mining method, a production rate of 6.2 Mt/y was estimated, with a forecast life of mine of 23 years.

The MCQ deposit is a large, blind copper-gold-silver porphyry-style deposit with a ground surface elevation of 2,200 metres above sea level (masl, on mountain) and around 400 m of caprock above the economic mineralisation.

Due to the caving constraints of the deposit, the first production level to initiate caving (undercut) is expected to be located around 100 m below the top of the mineralisation at 1,675 masl (circa-525 m below the top of the mountain), with the mining block extended around 550 m in depth (20 production levels at 27.5 m interlevel spacings).

The main ore transfer horizon is located 75 m higher in elevation than the mine access portals at 1,080 masl and the proposed valley infrastructure. The initial mining block will be accessed by twin tunnels developed in parallel for 2 km at which point a single access ramp will branch up towards the undercut; the twin tunnels will continue another 3.7 km to the base of the SLC where the crushing and conveying facilities will be located.

The company is currently weighing up whether to use tunnel boring machines or drill and blast to establish these tunnels.

Nienaber confirmed the 20 level SLC panel cave layout would involve 161 km of lateral development and 14 km of vertical development. There would be six ore pass connections on each level, four of these being ‘primary’ and two acting as backups. The crusher would be located on the 1155 bottom production level.

Due to the ventilation requirements in Colombia the mining fleet selected for Quebradona is predominantly electric, Nienaber said, adding that the units will initially be electric cable loaders powered by 1,000 v infrastructure.

Fourteen tonne LHDs were selected for the production levels based on their speed, bucket size (enables side-to-side loading in the crosscut and identification of oversize material) and cable length, the authors said. On the transfer level, 25 t loaders were specified to accommodate the shorter tramming lengths and limited operating areas (there are a maximum of two loaders per side of the crusher due to the layout).

As battery technology improves in the coming years, the selection of loader sizes may change as additional options become available, according to the authors.

The selection of the present Sandvik fleet was predominantly based on the electric loaders and the OEM’s ability to provide other front-line development and production machines required to undertake SLC mining, the authors said.

This decision also accounted for the use of automation for the majority of production activities, with the use of a common platform seen as the most pragmatic option at this stage.

It has also been proposed that the maintenance of the machines be carried out by Sandvik under a maintenance and repair style contract since there is a heavy reliance on the OEM’s equipment and systems.

An integrated materials handling system for the SLC was designed from the ore pass grizzlies, located on the production levels, to the process plant.

Due to the length of the ore passes (up to 500 m), and the predicted comminution expected by the time the rock appears on the transfer level, larger than industry standard grizzly apertures of 1,500 mm have been selected.

The design criteria for the underground crusher was that it needed to reduce the ore to a size suitable for placement on the conveyor belt and delivery to the surface coarse ore stockpile, after which secondary crushing prior to delivery at the process plant will be undertaken.

Assuming the maximum size reduction ratio for the crusher of circa-6:1 at a throughput rate of 6.2 Mt/y, a 51 in (1,295 mm) gyratory crusher was selected. This crusher is also suitable to support block cave mining should the conversion of mining method occur, according to the authors.

The process plant will include high pressure grinding rolls as the main crushing unit on the surface, supported by a secondary crusher to deal with oversize material. The ore then feeds to a ball mill before being discharged to the flotation circuit.

The gold-enriched copper concentrate will be piped to the filter plant for drying and the removal of water down to a moisture content of 10%, according to the company, while the tailings will be segregated to pyrite and non-pyrite streams before being distributed to one of two filter presses.

Dry stacking of the tailings will be used, with the pyrite-bearing tailings being encapsulated within the larger inert tailings footprint.

With the feasibility study due before the end of the year – and, pending a successful outcome – the proposed site execution works could start in the September quarter of 2021, Nienaber said.

Cononish hits pour milestone on way to becoming Scotland’s first commercial gold mine

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Scotgold Resources has poured first gold at its Cononish underground gold and silver mine, in the Scottish Grampian Mountains area.

Following this first pour – a major milestone in the commissioning of the processing plant – the company is aiming to ramp up production at Cononish to design level early in 2021, taking its place as Scotland’s first commercial gold mine.

In line with its phased development program, Scotgold is now focused on completing an accelerated expansion plan to increase production at the mine to 23,500 oz/y. The current Phase 1 is targeting an annual rate of ore production of 36,000 t and total gold production of 9,910 oz in 2021. Phase 2 will focus on doubling the annual rate of ore production to 72,000 t and a more than doubling in average annual gold production to 23,500 oz.

The company is fully funded to achieve Phase 2 expansion by May 2022, 17 months from the commencement of Phase 1 production.

The current reserve of gold at Cononish is confined to a single narrow, near vertical quartz vein extending above and below the main access on 400 m level, which was originally developed for exploration purposes between 1989 and 1991. The mining method selected for the orebody is retreat, sublevel open stoping.

Scotgold CEO, Richard Gray, said: “Our first gold pour is not only a significant milestone in the development of our Cononish gold and silver project but a milestone on the road to a Scottish gold mining industry. Today’s news is therefore a landmark event both for the company and for Scotland.”

First Ore Mining and Metso Outotec strike thickening plant deal for Pavlovskoye

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The First Ore Mining Company (FOMC), part of ARMZ Uranium Holding Co, says it has signed a cooperation agreement with Metso Outotec “underlining the parties’ interest in continuing their strategic partnership in the design, supply, installation, control and commissioning of the thickening plant for the Pavlovskoye field”.

The agreement waas signed by Igor Semenov (right), Executive Director, FOMC JSC, and Markku Teräsvasara (left), Vice President, Metso Outotec.

The Pavlovskoye polymetallic deposit on the Novaya Zemlya archipelago is the largest such deposit in Russia with 47.7 Mt of ore reserves (2.49 Mt f zinc, 549,000 t of lead and 1,194 t of silver), according to First Ore Mining.

The cooperation with Finland’s Outotec (since merged with Metso to make Metso Outotec) emerged more than a year ago on the sidelines of the St. Petersburg International Economic Forum, which gave rise to an initial pact. Since that time, the company’s experts, together with Aker Arctic Technology, have elaborated a detailed draft design for the floating concentrator and set out a preliminary thickening flow chart and main equipment layout, First Ore Mining said.

In September, representatives from Metso Outotec visited the Pavlovskoye field. In the course of the field activities, the company examined the site for the planned thickening plant, tailings pond and infrastructure facilities, First Ore Mining said. It also acknowledged the ore samples were representative and could be used in testing.

The next stage within the partnership will include tests to be carried out at Metso Outotec Research Center in Pori, Finland. Once the work is completed and the final thickening flow chart is developed, Metso Outotec will present the guaranteed performance indicators and design values to ensure the plant’s productivity and the high quality of the concentrates and metal extraction for the ore types studied, FOMC said.

Semenov said: “I am confident that working together with Metso Outotec will significantly improve the thickening indicators for Pavlovskoye ores, which were obtained during the studies in the previous years. As a result, we will produce premium concentrates that are in demand in the global lead and zinc markets.”

Teräsvasara added: “Indeed, it is quite interesting to participate in the development of this unique project for processing minerals in the Russian Arctic. In addition to standard technological and economic matters, harsh weather conditions, lack of infrastructure, and high requirements to environmental safety in the vulnerable Arctic wildlife have made us search for the best available technologies to cover all these points.”

The Pavlovskoye project includes plans to build the northern-most mining and processing plant to produce lead and zinc concentrates, with First Ore Mining as the project operator.

MAG Silver and Fresnillo make processing leap at Juanicipio

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Fresnillo and MAG Silver Corp’s Juanicipio silver-gold-lead-zinc project, in Mexico, has reached a major milestone, with development material from the project being processed at the Fresnillo beneficiation plant during the September quarter.

The joint venture, owned 56% by Fresnillo and 44% by MAG, saw 42,476 t processed during the quarter, with total production of 394,000 oz of silver, 610 oz of gold, 138 t of lead and 174 t of zinc, Fresnillo reported.

This first development material was processed through the nearby Fresnillo processing plant (100% owned by Fresnillo) with the lead (silver-rich) and zinc concentrates treated at market terms under offtake agreements with Met-Mex Peñoles, SA De CV in Torreón, Mexico, MAG said. The revenue from this production, net of processing and treatment costs, will be used by the joint venture to offset cash requirements of the initial project capital, according to MAG.

“This first production from Juanicipio is a major milestone for the company,” George Paspalas, MAG Silver’s President and CEO, said. “The successful processing of development material not only provides cash flow to offset capex, but further de-risks the project as it heads toward commercial production. We are looking forward to the first production stope coming online in Q4 (December quarter) 2020, and our potential to continue to produce cash whilst we complete the process plant construction.”

Fresnillo expects to process an average of 16,000 t/mth of mineralised material from the joint venture through its processing facility to mid-2021, at which time the Juanicipio beneficiation plant is scheduled for commissioning.

Development continues on site and the final preparation of the first production stope was concluded during the September quarter. Also during the quarter, progress was achieved on the construction of the Juanicipio processing plant.

South32 adds Cat AD63 to Cannington underground trucking fleet

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Last month, Cat dealer Hastings Deering sent out the world’s first AD63 truck to South32’s Cannington silver-lead mine in Queensland, Australia.

With a 63 t payload, the AD63 is the largest underground truck in the Cat product line, and comes with best in class speed on grade, according to Hastings Deering.

Joe Russell, South32 Cannington Vice President Operations, told IM that since taking delivery of the articulated truck from Caterpillar, via Hastings Deering, the company had started work on tailoring the vehicle to the mine’s specific requirements.

“Once the truck enters full operation, it will replace an older vehicle in our fleet,” Russell said. “The AD63 will be used in conjunction with the rest of the underground trucking fleet to move material to various locations within the South32 Cannington mine site.”

Russell highlighted the vehicle’s Euro Stage V Cat C27 diesel engine when reflecting on the recent fleet addition.

“The AD63’s engine specifications will help us to further reduce emissions, resulting in good outcomes for the environment and underground air quality,” he said.

Released in April, the AD63 features a 5% increased payload and more torque for enhanced production capabilities compared with its predecessor, the AD60, Cat says.

Additional new features enhance operator ergonomics, maintenance access and safety, and data collection for machine health monitoring, according to the OEM.

South32’s Cannington underground mine produces about 3 Mt/y of ore.

BHP Olympic Dam looks for value in SciDev wastewater treatment solution

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SciDev has received a trial purchase order for its MaxiFlox chemistry from BHP’s Olympic Dam polymetallic mine, in South Australia, which will see the company transfer its waste processing expertise to the production side, Lewis Utting says.

Australia’s largest copper operation, Olympic Dam operates a fully integrated processing facility from ore to metal.

The SciDev trial, which includes an initial A$1 million ($717,526) purchase order for the MaxiFlox chemistry, reflecting about three months of consumption, is expected to start by the end of the year and last around six months. It will focus on the use of SciDev’s chemistries in the hydromet and concentrator sections of the processing plant, SciDev said.

SciDev’s South Australia-based staff will be on site to deliver the associated professional services.

SciDev Managing Director and Chief Executive Officer, Lewis Utting, said the order represented a significant opportunity for SciDev.

“The opportunity to transfer our chemistry and knowhow from the waste processing side directly to the production side of a mining operation reflects the potential for the company’s bespoke chemistries,” he said.

The Olympic Dam mine produced 171,600 t of copper cathode in the year to June 30, 2020, 7% higher than the same period a year earlier, alongside 145,972 oz of refined gold, 984,000 oz of silver and 3,678 t of uranium (all of which was from a concentrate).

MaxiFlox, meanwhile, is specifically designed for the treatment of wastewater across several industries, SciDev says. Products in the MaxiFlox range are supplied in both liquid and powder form across an extensive range of molecular weights and charge densities to solve industrial challenges.

The MaxiFlox chemistries are also being used in the tailings thickener at the Las Bambas copper mine, in Peru, following a trial purchase order from mine owner MMG.