Tag Archives: Nevada

Hycroft Mining continues evaluation of novel sulphide heap oxidation/leach process

After testing out a “novel” oxidation and leaching process at the Hycroft Mine in Nevada, USA, Hycroft Mining Holding Corp is making plans to go back to a conventional oxide leaching setup in 2021.

The company produced 27,392 oz of gold and 178,836 oz of silver in 2020, an almost three-fold increase over 2019. It hit these numbers while operating at a pre-commercial scale using the novel process, which oxidises sulphides ahead of leaching.

It is now planning for run-of-mine production of 45,000-55,000 oz of gold and 400,000-450,000 oz of silver in 2021 using conventional cyanide heap leach.

It is anticipated that mining in the first four months of 2021 will be performed using the existing Hycroft fleet and a rental fleet, moving approximately 1.5 Mt/mth of ore and waste. For the remainder of the year, Hycroft intends to mine some 500,000 t of oxide and transitional ore and waste per month with a more cost-effective mining fleet.

Diane R Garrett, President & Chief Executive Officer, reflected on the results: “2020 was an important year for Hycroft as the company continued to focus on the restart of the Hycroft Mine. Throughout the year, we advanced work on the proprietary two-stage sulphide heap oxidation and leach process and made several important findings that will need to be addressed prior to our implementing the novel technology on a commercial scale.

“In 2021, we expect to mine predominantly oxide and transition material, which are more economic when treated using a conventional run-of-mine heap leaching method, which gives us the opportunity to continue to refine the operating parameters and flowsheet for the new heap leach pad and novel process. While the company continued to make significant progress in better understanding this proprietary process and its application on a commercial scale, the past year also presented some operational challenges, including learning to navigate in a newly emerged COVID-19 world.”

In the last few months, Hycroft says it has worked alongside consultants to identify and investigate opportunities for improvements in operating parameters for the two-stage sulphide heap oxidisation and leach process. The result of the work to date has identified several items that were not considered or included in the original plan and design but are critical to the success of this process. These findings include:

  • Adding a forced air injection system for the leach pad which is a key component of the oxidation process;
  • Developing a system for segregating solution flows to and from the heap leach pad to avoid co-mingling of solutions among heap lifts and ore processing stages that negatively impact recoveries and conditions on the leach pads;
  • Identifying that the finer crushed material requires agglomeration in order to achieve optimal permeability and gold/silver recoveries;
  • Understanding that higher soda ash, caustic soda, and cyanide consumption will be required which Hycroft experienced throughout the 2020 pre-commercial test pad programs and recently confirmed through the review of the test work;
  • Determining that some transitional ores are more economically attractive when processed as direct leach, run-of-mine material; and
  • Concluding that additional variability metallurgical and mineralogy studies will be required to better understand each of the geometallurgical domains in the orebody. While there was some variability work completed in the past, the recent test work has revealed that additional variability test work and compositing is necessary to fully understand the geometallurgy of each domain, and that additional sampling, including sampling below the water table where the predominance of the sulphide resources exist, is required given the complexity and variability of the large orebody.

The additional variability test work will also include detailed mineralogy studies as it is important to understand the role other minerals may play in the overall oxidation process and to enhance Hycroft’s ability to measure oxidation rates accurately and consistently, it said.

The team at Hycroft has developed an approximate $10 million program for drilling and additional metallurgical and mineralogical studies in 2021. This program of work has been approved by the Board of Directors of Hycroft and can be funded from existing cash and Hycroft’s current operating plans.

Hycroft expects to mine and stockpile at least 300,000 tons (272,155 t) of sulphide ore in 2021 that, once sufficient additional work on the novel process has been completed, will be available for testing to further refine operating parameters and measure its performance for large scale application of the oxidation heap leach.

Garrett added: “2021 is a foundational year designed to advance the work necessary in preparation for larger-scale sulphide operations. The team is working diligently to optimise current and future heap leach mine plans and to evaluate all opportunities for more profitable mine plans in the near and medium term. This work involves taking a ‘ground up’ approach working from the orebody out. The company’s prior plan was developed using a $1,200/oz gold price pit shell which leaves profitable ore behind in the current gold and silver price environment. By running pit shells at recent gold and silver prices, we have identified additional areas of oxide mineralisation that can generate cash flows over the next several years and we have already begun to identify areas of higher-grade mineralisation that will become important for mine sequencing and further improving cash flows prior to accessing sulphide material.”

As the company considers life-of-mine development and planning for the Hycroft deposit, particularly in the current gold and silver price environment, Hycroft says it is prudent to evaluate proven processing technologies for treating some ore types that may be more profitable than only using the two-stage sulphide heap oxidation and leaching process.

Potential opportunities being examined by the company in 2021 include: developing an understanding of the grade range distribution of the sulphide material; completing on-going work on the higher-grade areas of Hycroft; and following up on historical high-grade intercepts.

In order to capitalise on these potential opportunities, which take advantage of the current commodity price environment, Hycroft believes that it should also evaluate the benefits of a multi-process operation. Long-term operating scenarios may include conventional run-of-mine cyanide heap leaching for the oxide and transitional material, sulphide heap oxidation and leaching using the novel process, and an appropriately sized milling and flotation plant for processing the higher-grade ranges of sulphide material.

“The company believes that the plan it has put in place for 2021 will provide the new team the time to fully consider and evaluate these opportunities and make any necessary changes to improve the leach pads, process plants and process flowsheet, maintain and develop its workforce, and advance the project, in order to further enhance the value of the project,” it said. “As the test work advances and alternative processes are considered, the company expects to perform technical studies and trade-off evaluations which may result in an updated feasibility study.”

Schlumberger aims to fast-track lithium brine extraction with DLE technology

Schlumberger New Energy has announced the development of a lithium extraction pilot plant in Clayton Valley, Nevada, through its new venture, NeoLith Energy.

The NeoLith Energy sustainable approach uses a differentiated direct lithium extraction (DLE) process to enable the production of high-purity, battery-grade lithium material while reducing the production time from over a year to weeks, the company claims.

“This innovative process can create new market opportunities for lithium extraction and battery manufacturing economy, and maximise the value of the lithium-rich resource base in Nevada with cutting-edge extraction technology,” it said.

NeoLith Energy’s pilot plant is a step towards a full-scale, commercial lithium production facility. The pilot plant results will be used to optimise the design of the full-scale production plant.

The production plant will use an environmentally friendly method for subsurface brine extraction and lithium production that requires a significantly smaller footprint and reduces water consumption by over 85% compared with current methods for lithium extraction from brine, it said.

Ashok Belani, Schlumberger New Energy Executive Vice President, said: “Nevada lithium resources present an excellent opportunity to demonstrate a leap in production efficiency with a more sustainable approach. Schlumberger’s expertise in the subsurface domain, development of process technology, and global deployment of technology at scale with various partners all play an important role in the innovation and efficiency of our DLE process. We are accelerating the deployment of our pilot plant in response to the high market demand for battery-grade lithium material.”

The pilot plant’s deployment is part of the Pure Energy Minerals agreement with Schlumberger New Energy for the development of its Nevada lithium brine property, using advanced technology to process the brine and extract high-purity lithium, maximising the lithium resource recovery.

Pure Energy Minerals previously developed a pilot plant design for the extraction of lithium brine through a design led by Tenova Advanced Technologies with significant contributions from SUEZ Water Technologies & Solutions, a business unit of SUEZ Group, and NORAM Engineering & Constructors. The facility at the project would have been the first pilot-scale implementation of the Tenova Process in the world, a process specifically designed to exclude solar pond evaporation, increase and accelerate lithium recovery, and reduce the associated environmental footprint of lithium production.

Commissioning of the DLE pilot plant will begin following receipt of all necessary permits, Schlumberger New Energy said. NeoLith Energy intends to begin operations before the end of 2021.

Schlumberger New Energy has invested more than $15 million in this DLE process and expects the development and operation of the pilot plant in Nevada to require a similar amount of investment.

This DLE process has the potential to disrupt the lithium economy by opening new opportunities to existing production regions and enabling new lithium production regions across the globe to meet the growing demand, it says.

ioneer signs MoU with Caterpillar to introduce autonomous haulage at Rhyolite Ridge

ioneer Ltd says it has completed a joint automation study with Caterpillar and the Cat dealer for Nevada, Cashman Equipment Company, and signed a memorandum of understanding with Cat that should see autonomous haulage employed at the Rhyolite Ridge lithium-boron project in Esmerelda County.

The study was targeting the early introduction of Cat’s Command for hauling Autonomous Haulage System (AHS) at Rhyolite Ridge, with the results of the Rhyolite Ridge feasibility study showing the viability of AHS at the mine and how its proposed application could positively impact the overall cost structure of the operations.

Key anticipated drivers include increased operating hours, reduced cycle times and improved cycle efficiency, and decreased operating costs in terms of maintenance, fuel, labour and tyres. AHS should also lead to improved in-cycle productivity and overall utilisation, reducing the number of trucks required, ioneer said.

To date, Cat autonomous mining trucks have safely hauled more than 2 billion tonnes of material worldwide, driving over 67.6 million km without a lost-time injury in the process.

The Rhyolite Ridge operations are scheduled to start in 2023 with a fleet of Cat 785 Next Generation mining trucks (pictured) equipped with Cat Command for hauling, and the fleet is scheduled to expand significantly in year four, ioneer explained. All support equipment will feature the latest MineStar technology using high-precision GPS and real-time analytics to maximise efficiency and accuracy in material loading, it added.

This will be the first greenfield operation in North America to use AHS and will mark the expansion of Command for hauling automation technology to the 140-t class Cat 785 Next Generation mining truck.

The MoU between Cat and ioneer is for the use of Cat Command for hauling at the Rhyolite Ridge mine. The companies have engaged in preliminary, non-binding negotiations regarding the terms of the proposed transaction and intend to negotiate formal agreements in the coming months, ioneer said.

The partnership will operate through Cashman Equipment, Nevada’s Caterpillar dealership since 1931. The fleet and initial auxiliary equipment will all be equipped with Cat MineStar Terrain, sold and supported by Intermountain Mining Technologies. This GPS system provides improved data for drilling, excavation, grading and dozing and should allow for better delineation of the overburden and ore for Rhyolite Ridge, according to ioneer.

As stated in the October 2020 release, the equipment and services supplied by Caterpillar during the first five years of operation is valued at around $100 million and may be financed through Caterpillar Financial Services.

ioneer’s managing director, Bernard Rowe, said: “Our agreement with Caterpillar represents much more than just the purchase of equipment; it is a true ongoing partnership as we commence production at Rhyolite Ridge.

“We are very pleased with the results of the automation study and look forward to working with Caterpillar, Cashman, and Intermountain Mining Technology in our effort to produce materials that are vital to a sustainable future. The incorporation of an autonomous haulage system and other Caterpillar technologies at Rhyolite Ridge will only further our goal to improve project safety and operational efficiency.”

Jim Hawkins, General Manager of MineStar Solutions of Caterpillar Inc, said: “Caterpillar mining technologies, including Command for hauling, deliver mining companies throughout the world benefit from greater productivity, increased truck utilisation, consistent truck operation and reduced costs. We are excited to support ioneer to deliver these same advantages to the Rhyolite Ridge greenfield mining opportunity.”

The Rhyolite Ridge project is the only one of its type known globally, according to the DFS from Fluor. Its unique mineralogical characteristics support low-cost processing of its ore into high-grade lithium and boric acid products using sulphuric acid leaching.

An initial starter pit at the project will be developed in the southwestern part of the orebody to supply ore for the first 4.5 years. In this area, lithium grades are 15% higher than the average grade for the deposit and the ore is more exposed at surface. Development of the greater pit will start once the environmental permits for this development have been granted.

The Stage 2 pit design will facilitate a larger mining area to be maintained, aiding the efficiency of the operation for another 21 years, according to Fluor. Stage 2 will involve expansion to the south and east. Finally, mining will progress to the north of the deposit. The Stage 2 pit requires prestripping to begin in year four.

SNC-Lavalin to manage construction of Coeur’s Rochester silver-gold mine expansion

SNC-Lavalin has been awarded a $30 million contract by Coeur Rochester Inc, a wholly-owned subsidiary of Coeur Mining, to provide construction management services for the Plan of Operations, Amendment Number 11 (POA 11) expansion project, at Coeur’s Rochester mine near Lovelock, Nevada, USA.

The contract commenced in the December quarter and is estimated to be completed by the end of 2022. This win is aligned with SNC-Lavalin’s new strategy moving forward in the Services segment, it said.

The POA 11 expansion project includes the construction of a new crushing plant, including a primary, secondary and tertiary crushing circuit (high pressure grinding rolls), a new heap leach pad (272 Mt), a new Merrill-Crowe process plant (62,509 litres/min), and upgrades to existing electrical utility system infrastructure, including a new substation and power distribution lines.

Coeur says this will more than double planned annual crusher throughput capacity from around 12.7 Mt to over 25.4 Mt, post-expansion. This will see average annual silver and gold production total over 8 Moz and some 80,000 oz, respectively, for the initial 10 years, post-expansion

SNC-Lavalin said: “This mandate is well aligned with our expertise in silver, gold and base metal project delivery as well as our commitment to delivering real value to our clients.”

SNC-Lavalin’s offices in Reno, Nevada, and Toronto, Ontario, will continue to support the construction management phase of the project. In addition, a team based locally at the site will manage construction-related activities.

César Inostroza, Senior Vice-President, Mining & Metallurgy, SNC-Lavalin, said: “SNC-Lavalin’s Mining & Metallurgy strategic plan is gaining traction with this mandate. It is an example of the mining services work that our team is winning across our core geographies, including the USA. SNC-Lavalin and Coeur continue to foster a strong relationship that finds and executes services solutions to create world-class operations

“This award is a testament to the continued partnership between SNC-Lavalin and Coeur. It leverages our knowledge of the Rochester mine and engineering expertise from the previous phase of this project and expands our work in the US.”

Terrence FD Smith, Coeur’s Senior Vice President and Chief Development Officer, added: “The strong business partnership between Coeur and SNC-Lavalin will help ensure a robust project delivery for Rochester, paving the way for improved performance in the future.”

Since approval of the initial Plan of Operation in 1986, the Rochester mine has undergone periodic mine plan amendments to support development projects and continued operations. The POA 11 proposes another mine life extension, which is expected to maintain the current workforce and support full production activities at Rochester until 2033.

Americas Gold and Silver hits commercial mark at Relief Canyon gold mine

Americas Gold and Silver says its Relief Canyon mine, in Nevada, USA, has declared commercial production, effective January 11, 2021.

The company poured first gold from the operation back in February 2020, but the failure of its radial stacker in May pushed the company’s initial commercial production guidance offline.

Its large radial stacker returned to operation on the Relief Canyon leach pad back in December, allowing ore placement to return to the targeted rate of around 14,500 t/d, up from the circa-7,250 t/d rate achieved with a temporary stacking solution.

The company is now targeting full ramp-up from the operation by mid-May 2021.

Americas Gold and Silver President & CEO, Darren Blasutti, said: “I am pleased to announce that Relief Canyon has achieved commercial production following a challenging 2020. The Relief Canyon team worked hard to overcome the common teething pains in commissioning a new operation, the impact of the COVID-19 pandemic, and the failure of our large radial stacker.

“I look forward to a successful 2021.”

Sandvik and Barrick confirm Artisan Z50 trials at Turquoise Ridge gold mine

Sandvik and Barrick have confirmed the signing of a partnership agreement for trialing and enhancing battery-electric vehicles (BEVs) for underground hard-rock mining.

During a three-year production trial, Sandvik will deploy four Artisan Z50 BEV trucks at the Turquoise Ridge gold mine, part of the Nevada Gold Mines joint venture (JV), Sandvik said. Barrick is the operator of the JV, which is the single-largest gold-producing complex in the world, forecast to produce a total of 3.4-3.65 Moz of gold during 2020.

The announcement follows an acknowledgement of such a deal by President of Sandvik Mining and Rock Technology, Henrik Ager, earlier this month.

The Z50 haul truck, with a 50 t payload capacity, is a ground-up design that seamlessly integrates the most capable and proven battery electric powertrain available in the mining industry with the latest and most coveted features of any haul truck on the market today, according to Sandvik.

It is equipped with AutoSwap, a patented self-swapping system for the Artisan battery pack. This makes battery swapping faster and easier with a minimum amount of manual handling: changing the battery only takes about six minutes, and it can be done in a passing bay or old re-muck bay with no overhead cranes or external infrastructure needed.

In phase 1 trials, the Z50 truck already achieved more than 1,400 hours of production with over 1,400 loads, according to Sandvik. It reached production operation of up to 18 hours per day, with speeds of over 10 km/h observed on the ramp to the tip.

Some of the key performance indicators in the new partnership will include the performance of the BEV technology in a production environment, mechanical availability, average lifecycle cost and overall production cost, Sandvik said.

“We are always looking at ways to improve our performance, both in terms of sustainability and operational efficiency,”  Mark Bristow, Barrick’s President and CEO, said. “This partnership with Sandvik is exciting and will give us first-hand experience in BEV technology in our own production environment. It is a significant step to furthering our BEV strategy across the group.”

Ager added: “I am very pleased that Barrick and Sandvik have teamed up to perform these extensive trials in a daily production environment. It gives us the possibility to prove the performance of our BEV technology.

“The purely battery-powered truck helps to reduce heat and emissions underground, helping mines reach their sustainability targets and reduce ventilation costs. This raises the bar for what is possible and enables an all-new level of production and cost reduction for underground hard rock mines.”

A dedicated site project team will be jointly working with the Barrick operations team during the trial period to ensure that all data is captured and the experience from both Sandvik and Barrick is used to ensure the uptime and productivity targets are met, Sandvik said.

Barrick to receive three more Artisan Z50 battery-electric trucks, Ager says

Sandvik Mining and Rock Technology has signed an agreement with Barrick Gold that could see four Artisan Z50 battery-electric trucks deployed at the miner’s majority-owned operations in Nevada, Henrik Ager confirmed this week.

Speaking at Sandvik’s Capital Markets Day on Tuesday, Ager, President of Sandvik Mining and Rock Technology (soon to be President of Sandvik Mining and Rock Solutions), said the company had just signed “a cooperation partnership” with Barrick in relation to the delivery.

“We have one (truck) operating already and have three coming,” he said.

Back in May, a Barrick spokesperson confirmed to IM that an ongoing trial involving a 50-t payload Z50 was expected to be finalised in the June quarter of this year, “with the option to extend, should the KPIs not be met”. The machine was being tested at Turquoise Ridge, a gold mine operated under the Nevada Gold Mines company, owned 61.5% by Barrick and 38.5% by Newmont.

Based on this order, IM assumes the Turquoise Ridge trial was a success.

Alongside this reveal, Ager, talking up the company’s next-generation AutoMine® Concept vehicle recently revealed at the Innovation in Mining event, said the company currently had automation solutions at 59 sites across the mining industry. This compared favourably with solutions at 43 sites 18 months ago, and 19 sites back in 2016.

Mader Group to maintain heavy equipment fleet at Nevada Gold Mines

Mader Group says it has entered into a contract with Nevada Gold Mines for the provision of heavy equipment maintenance.

The ASX-listed contractor will be responsible for providing skilled labour for mechanical and electrical maintenance, machining, scheduling and planning to Nevada Gold Mines, a joint venture between Barrick Gold and Newmont, to ensure the upkeep of heavy mobile equipment operating standards.

The three-year contract will see Mader Group deliver maintenance labour services across Nevada Gold Mines’ eight mine sites, associated infrastructure and processing facilities (all located in Nevada).

Mader Chief Executive, Patrick Conway, commended the team’s track record and growing capability since launching operations in the US.

“This is just one of several key contracts ensuring our continued expansion in the region,” Conway said. “It gives us great pleasure to support Nevada Gold Mines in what is likely to be a fruitful and long-lasting relationship. Forecasting 2.1-2.25 Moz of gold production in 2020, Nevada Gold Mines is expected to account for approximately 30% of total US gold production with optimal fleet performance a critical component in achieving their targets. We look forward to providing a top tier and dependable maintenance service to back their success.”

Corvus Gold weighs heap leach, BIOX route at Mother Lode project

Corvus Gold has announced the results of a preliminary economic assessment (PEA) for its Mother Lode project (MLP) in southwest Nevada, USA.

The study outlines a project able to produce 170,980 oz/y of gold and 79,600 oz/y of silver through a combination of heap leaching and biological oxidation (BIOX).

Based off measured and indicated resources of 1.55 Moz of gold and 1.51 Moz of silver, and inferred resources of 170,000 oz of gold and 400,000 oz of silver, the study estimated an operation with an eight-year mine life and an initial price tag of $406 million. Using a $1,500/oz gold price, the payback period was estimated at 2.7 years.

Jeffrey Pontius, President and CEO of Corvus, said: “The results from our initial PEA study of the Mother Lode standalone project are encouraging. The potential projected annual gold production of over 200,000 oz/y during the first three years is significant, especially as a new project, which could provide an increase to the Corvus Gold future production profile. The PEA demonstrates the preliminary potential for the project, on its own, to produce significant free cash flow and after-tax NPV.

“Corvus now has a number of strategic alternatives available to it to drive shareholder value. Given the recent interest in the Bullfrog Gold District from multiple producing companies with adjacent land packages, Corvus’ compelling and accretive projects and its commanding land position with what we believe is demonstrated high exploration potential, has positioned the company to deliver increased shareholder value.”

The Mother Lode project is modelled as a large, open pit, with a biological oxidation mill to treat the higher-grade sulphide mineralisation and a heap leach pad for treatment of oxide mineralisation. The mining plan uses standard mining practices and has a production scale that is currently being used by many operating mines, the company said.

The new PEA study, which assumes a standalone project, also includes a number of other changes to the previously assumed concept for the combined Mother Lode-North Bullfrog project configuration, which enhance the project. This includes:

  • Employing BIOX to treat the MLP sulphide mineralisation would increase gold recovery by 11%. Metallurgical testing of a stirred BIOX process on the MLP whole sulphide mineralisation from Mother Lode demonstrated gold recoveries of 91-92% as compared with the previous testing on MLP flotation concentrate;
  • Eliminating the need for the concentrator, oxygen plant and autoclave components of the previous plant concept simplified the plant conceptual design and would reduce the process plant capital cost;
  • Ongoing work expanding Mother Lode resources in the CIZ area and the main Zone with ongoing work at improving the open-pit mining and development plans will enhance project economics; and
  • New experimental work on conducting the BIOX process in a heap is being tested as follow-up on past successful studies and could substantially cut operation and capital costs with the elimination of the mill circuit.

The PEA only includes drill results completed up until September 2020. In addition, Corvus will continue follow-up mineral resource expansion work and new discovery drilling on priority targets at both the North Bullfrog and Mother Lode properties through 2021, it said.

MineWare Argus Wheel Loader achieves North America first with CAT 992 installation

MineWare’s new Argus Wheel Loader has made its debut in North America, with the OEM-independent wheel loader monitoring system having recently been installed on a CAT 992K operating at a gold mine in Nevada, USA.

The system, purchased to improve wheel loader truck payload management and performance at the operation, was installed in July by the company’s North America team.

On top of it being the first commercial deployment of MineWare’s Argus WL monitoring system in the North America region, it is also MineWare’s first system installation on a CAT 992K wheel loader, the company told IM.

The release of Argus WL in February followed 18 months of field trials conducted across three Western Australia mine sites.

Argus WL improves wheel loader efficiency, effectiveness and payload accuracy, according to the Komatsu-owned company. “The system weighs each bucket in real time, without the need to stop and calculate payload before dumping the load,” it said.

“Often dubbed as ‘support’ equipment, the wheel loader makes it possible for the primary loading and hauling equipment to do their jobs more efficiently,” MineWare said. “When a large wheel loader has the capacity to replace a small digger, it’s vital not to forget the importance of these assets and the impact they have on mining productivity and profitability.”

The company concluded: “MineWare’s Argus Wheel Loader system is OEM independent/agnostic. Our ‘all makes, all models’ approach gives customers the best opportunity to standardise systems across mixed fleets of equipment.

“For example, on this one particular customer site, MineWare supports three different equipment makes and models: Komatsu, Hitachi and CAT.”