Tag Archives: Arizona

Taseko Mines starts commercial construction move at Florence ISR copper project

Taseko Mines, having just completed a $400 million bond refinancing and fundraising program, is moving forward with developing a commercial operation at its Florence in-situ recovery (ISR) copper project in Arizona, USA.

Capital requirements for the commercial production facility at Florence, which followed an ISR pilot project, are estimated at $230 million.

Pending final regulatory approvals and financing, Taseko has previously stated it could start construction of the commercial operation this year, with first production in late 2022.

Stuart McDonald, President of Taseko, said: “With the majority of the required funding for our Florence Copper project now in hand, we are moving forward with final design engineering of the commercial production facility as well as procurement of certain critical components.”

McDonald said the company is continuing to advance discussions with potential joint venture partners at Florence, but its strong cash balance and improved Gibraltar mine cash flows from copper prices currently over $3.70/Ib ($8,159/t) means it has “numerous options available” to obtain the remaining funding.

Russell Hallbauer, CEO of Taseko, added on Florence: “Florence is one of the least capital-intensive copper production facilities in the world and, when fully ramped up, will produce 40,000 t of high-quality cathode copper annually for the US domestic market.

“It is a green project, with carbon emissions and water and energy consumption all dramatically lower than a conventional mine, and, with C1 operating costs of $0.90/Ib of copper, it will also be in the lowest quartile of the global cost curve.”

Capstone considering Eriez HydroFloat tech to boost Pinto Valley performance

Capstone Mining is continuing to leverage innovative, low-cost technology at its Pinto Valley mine in an attempt to further utilise its existing solvent-extraction and electowinning (SX-EW) plant at the Arizona, USA, operation.

In the December quarter of 2019, Pinto Valley commenced a PV3 Optimization project designed to achieve safer, more reliable and higher capacity operations without major investments in new comminution equipment. A goal was set to achieve increased reliability, and higher throughput at maximised copper recovery with lower costs by leveraging new inexpensive technologies.

In its September quarter results, the company provided an update on this project, saying, to October 27, it had spent $17 million as part of its Phase 1 developments. This included crushing and mill equipment replacements, which are 60% complete with full completion expected by July 2021.

As part of its Phase 2 developments, Capstone spent $10 million in conveyor, mill auto controls, cyclone packs and tailings thickener upgrades. These upgrades are planned to be completed by the end of the September quarter of 2021.

On top of this, the miner completed a blast fragmentation optimisation project to target 30% fines (minus-0.5 in) in run of mine feed in the June quarter. In the same quarter, it completed a $300,000 tele-remote Cat D10 Dozer project to increase worker safety for high-risk applications. Another $6 million was spent on new mine equipment to increase efficiency while lowering diesel consumption, greenhouse gas emissions and other operating costs by $800,000/y. This project was completed in the September quarter.

In terms of its metallurgical innovation, the company continued to use novel catalytic technology developed by Jetti Resources at Pinto Valley, expected to deliver 300-350 MIb of copper cathode over the next 20 years from high-grade mine waste and historic stockpiles at all-in costs under $2/Ib. This technology uses a catalyst on primary sulphide minerals to disrupt the sulphur metal bond of the mineral and allow for a leaching solution to contact the copper. This enables the extraction of the metal to take place unimpeded.

Capstone also made plans to use new reagents to improve worker safety and improve overall metallurgical performance at its molybdenum plant re-start project. This would involve “minimal capital” and completion was targeted by the March quarter of 2021, it said.

Capstone says it is targeting to reach 60,000-63,000 t average daily throughput at Pinto Valley at an 85-90% recovery by 2022-2023. This is 17-30% higher than 2019 performance and is subject to further test work and studies to be completed in the first half of 2021, including tailings management, the company explained.

Added to this, following positive laboratory results on Pinto Valley flotation circuit samples, Capstone and Eriez are planning to commence pilot plant testing of the HydroFloat technology.

The HydroFloat fluidised bed assisted flotation cell has previously proven effective at floating coarse ore particles, up to two to three times the size limit of conventional flotation cells in commercial applications such as at Newcrest Mining’s Cadia Valley operation in Australia. Newcrest has recently decided to expand the use of this technology at the operation.

Capstone says the lab results at Pinto Valley had led Eriez to report an opportunity to reduce copper losses by up to 50%, thereby boosting overall recovery by up to 6% at Pinto Valley.

“Furthermore, the ability to recover coarse particles could allow for higher mill throughput while achieving high copper recovery,” Capstone said.

Other benefits could be lower grinding costs, lower water and energy consumption and increased tailings stability via coarser tailings.

Pilot testing is due to commence in November with results expected back in the March quarter of 2021.

Lastly, work on PV4 expansion scenarios to take advantage of around one billion tonnes of measured and indicated resources at 0.30% Cu continued during the September quarter.

“Given management’s confidence in PV3 Optimization progress to date, including the successful implementation of the novel catalytic technology from Jetti Resources to enhance leaching performance, Capstone has decided to evaluate expansion scenarios using existing assets rather than building new mill infrastructure,” the company said.

The study is assessing higher mining rates, higher cutoff grades to the mill, and an increased tonnage available for leaching.

While a significant mill expansion is not currently being contemplated, an expansion of Pinto Valley’s SX-EW capacity of 25 MIb/y may be necessary, it said. Extensive column leach test work will be conducted over 2021, with the overall PV4 expansion study expected to be released in 2022, Capstone added.

Taseko Mines eyes commercial production at Florence ISR copper project

Taseko Mines prospects of opening the US’ next commercial in-situ recovery (ISR) copper project have been strengthened following a recent hearing held by the Arizona Department of Environmental Quality (ADEQ).

At the public hearing, which came shortly after the ADEQ issued the company with a draft Aquifer Protection Permit (APP) for its commercial ISR project, Taseko’s plans for the development of the Florence copper project received “overwhelming support”, the company said.

The public hearing is a key part of the process for the granting of the full APP. It had participation from local community members, local business owners, elected state officials and city councillors, a state senator as well as representatives from the technical services sector, Taseko reported.

Russell Hallbauer, Chief Executive Officer and Director of Taseko, said: “30 interested parties spoke at the hearing, communicating great support for the company and the project, with only one individual not in favour. The ADEQ heard loud and clear that the community wants this project to advance to commercial operation.

“The company has worked very hard to inform the Florence community on not only the safeguards in place to ensure the environmental integrity of the project, but also the environmental benefits of the Florence copper extraction process. The extensive data collected from 18 months of operating the test facility is proof that the process works, both from a technical perspective as well as environmentally.”

The ADEQ will take written correspondence for another three weeks, until October 12, before writing and issuing the final permit, Taseko says.

Taseko commenced well field operations at its Florence ISR pilot project in central Arizona, US, in January 2019, reaching “commercial grade levels” less than six months after.

The commercial Florence mine is expected to have a copper production capacity of 85 MIb/y (38,555 t/y) and a 21-year mine life.

Lost Dutchman Mine ready to tell its metal separation tale

A company out of Arizona, USA, believes it has come up with a density separation technology that could upgrade heavy metal concentrates without the need for water or chemicals.

Lost Dutchman Mine (LDM), named after the legend of a rich Arizona gold deposit discovered by an elusive Dutch prospector, never since located, is the company in question. Being supported along the way by the Centre for Excellence in Mining Innovation (CEMI) out of Sudbury, Ontario, the firm is looking to find a way into the mining sector at a time when environmental, social and governance (ESG) concerns have reached a new high.

Mark Ogram, one of three Co-founders of LDM, explained the company’s aim and name, saying: “We’ve been able to find gold where people could not find it.

“We have now come up with a solution that requires no chemicals or water to purify a gold ore.”

While gold is the company’s initial focus, the process can be applied to most heavy metals including silver, copper and tungsten, according to Ogram. Some encouraging results have also been seen removing sulphides from gold ore ahead of further processing, in addition to ‘cleaning’ coal, he added.

A gravity separation process that uses air flow rather than water to separate these materials by density, the obvious comparisons are with Knelson concentrators or other separation technologies – all of which tend to use water or another medium for their processes. Ogram says Knelson concentrators are also for free gold, not refractory gold, the latter of which the LDM technology can cope with.

allmineral’s allair® technology also comes to mind as a comparison. This is a process that leverages many of the functions of the water-operated alljig® technology but, instead, uses air as the pulsating medium. So far, allair’s applications have been confined to mostly coal and other minerals.

Like many of these technologies, it is feed preparation that will prove decisive for the application of LDM technology, with ore crush size and moisture content the two key factors.

“We don’t think we would need ball mills to get the feed down to the right size,” LDM Co-founder Ken Abbott said. “A standard crushing and screening setup should be suitable.”

While test work to date has been with material in the 30-60 mesh range, Abbott is confident the technology will work with material from 100-200 mesh.

“It will be a little more of a sensitive process, but it does work should people require it,” he said.

When it comes to moisture content, a drying process will most likely be needed ahead of feeding to the LDM unit.

“The material needs to flow freely to work well,” Abbott said.

In-field test work involved the company using a tumble-type continuous screener/dryer to reach the appropriate moisture content, but a more ‘industrial’ process will be required in commercial applications.

The best results are likely to be achieved when both factors are consistent, according to LDM.

“The system requires a steady and uniform distribution in the feed cycle that includes surge capacity and automated material flow to ensure a steady feed rate,” the company says.

Dale A Shay, a consultant with RIMCON advising LDM, said vat leaching operations were already producing material at the appropriate size for the LDM technology to be tested. “They are also reducing the moisture content to an appropriate level,” he said.

Despite this, the company feels tailings applications may be the most suitable place to start with. This harks back to the ESG concerns miners are feeling – some of which revolves around tailings impoundment areas – as well as the fact the ‘conservative’ mining industry is generally more comfortable testing new technologies on material they already consider to be ‘waste’.

For the technology to prove out, the company will have to scale up its testing.

LDM has, to date, carried out benchtop, laboratory scale and in-field tests on low-grade material, but it has only reached a 1 ton (0.9 t) per hour rate.

“We would put in a tonne and get a few grams out,” Ogram said. “That is how we developed the technology.”

Despite there being a linear progression of recoveries from benchtop to lab to the field, LDM will need to go bigger to find the widescale applications it is after.

Yet, its potential entry into the market is well timed.

Removing the use of chemicals and water in a process that will most likely come after initial crushing could prove cost-effective, as well as environmentally sound.

Yes, the air flow component and feed drying will consume power on mine sites, but this ‘upfront’ operating cost will pay off further downstream as not as much material will be transported to make its way down the process flowsheet. It is more likely to go straight to tailings or backfill material feed.

Abbott explains: “The technology drastically reduces the material that will move onto final concentration, which substantially reduces material movement on site.”

For new developments, there is a knock-on benefit for permitting; the regulatory boxes are much more likely to be ticked when the words ‘water’ and ‘cyanide’ are absent from applications.

LDM Co-founder, Wayne Rod, sums this up: “Although from a cost perspective, it is expected to be competitive with other concentration technologies, the real savings will come on the ESG front and being able to reduce any environmental issues you may have.”

This is a message Rod and the rest of the LDM team are taking to the headquarters of major mining companies, where executives and board members are treating ESG challenges like a ‘cost’ they need to reduce to stay viable.

“As that ESG issue becomes even more prevalent, I see technology becoming a much bigger focus area,” Rod says. “Taking water and chemicals out of the concentration process will help alleviate some of that pressure.”

Heap leach operations edge closer at Bonanza Harquahala gold mine

5D Mining & Construction Inc is to build the heap leach pad for the Bonanza Harquahala mine, in Arizona, USA, after signing a contract with project owners Tombstone Exploration and Goldrock Resources.

Phase One construction of the Bonanza heap leach project is anticipated to start on or about May 25, with full project completion expected by mid-September, Tombstone Exploration and Goldrock Resources said.

The news comes just a month after the project, owned 40% by Tombstone and 60% by Goldrock, was signed off for construction by the Arizona Department of Environmental Quality.

The contract will see 5D supply labor, equipment and materials to perform all of the civil work and liner installation for phase one, the companies said.

“We are now moving into the construction phase of the leach pad with an estimated completion of the construction within 12 to 16 weeks,” Tombstone CEO and President, Alan Brown, said. “Once the construction is complete, we will start moving an estimated 500,000 t onto the leach pad and begin an estimated six- to eight-month processing period for all of the mined material in Phase One. Once leaching has started, bi-weekly delivery of the carbon to our designated gold processing facility is expected.”

Based on past metallurgical testing, production is budgeted at 23,000 oz of gold with potential for more, according to Brown.

Bonanza Manager, Todd Fayram, said he was “highly confident” in the company’s test results and expected first gold pour in mid- to late-September.

Phase Two, currently under consideration, includes a much bigger package where the owners have potentially identified 150,000-300,000 oz of gold in defined underground targets in and around the old Harquahala mine with significant upside potential, they said.

The 5D contract for construction for this first phase of the Bonanza Heap Leach Project includes all survey work required for layout and grading, debrushing the work area, demolishing obstructing concrete structures, relocating and stockpiling the existing tailings, mass grading for the pregnant leach solution pond and leach pad, all trenching and backfill for the liner anchor trench, fine grading for the liner, installation of the liner and perforated drain pipe, including required support work.

5D has provided work for some of the largest companies in the world, including BHP, Capstone Mining Corp, Freeport-McMoRan, Grupo Mexico and many others.

Brown said: “This construction agreement is another significant milestone for Tombstone. After careful deliberation, we are pleased to name 5D – a highly recognised construction company – as our partner to execute the first phase of the Bonanza heap leach project.”

Metso invests in Arizona repair facility after stellar 2019 results

Metso has made further investments in its Mesa repair facility in Arizona, USA, in order to, it says, optimise safety and broaden service capabilities.

The facility offers repairs and field services while supporting Metso’s Life Cycle Services contracts. It has seen steady growth since the opening in 2015, with 2019 setting a record for safety performance, revenue and profitability, according to the company.

One of the many upgrades to the facility includes the installation of “a state-of-the-art stress relief oven”. This investment was made to offer a more complete service to customers on large rebuilds, Metso said. “This will improve quality control as well as accelerate the turnaround times for our clients,” the company explained.

In addition to the stress relief oven, Mesa has also invested in other equipment to support the repair of mining screens, Wet Low Intensity Magnetic Separator (LIMS) drums, and babbitted bearings for mills.

A screen test stand has been manufactured and will be operational by the end of March, the company said. This will allow each screen rebuilt at Mesa to be test-run before being sent back out into the field, which will reduce the potential for issues during installation and start-up, according to the company.

Equipment needed to repair LIMS drums was also put in place last year and has seen a steady inflow of repairs coming from mines in the Iron Range of Minnesota, the company said.

Metso said: “In the future, the facility aims to further grow its portfolio of value-added services, to improve productivity and reduce operational costs for its clients in both the mining and aggregates sectors.”

Marks reveals Resolution copper concentrator details at SME

There’s some good news for mineral processing equipment suppliers looking to win business from the Resolution copper mine in Arizona, USA: the Rio Tinto/BHP-owned project already has a preliminary concentrator plan in place.

The sticking point is that, according to Anita Marks, Principal Advisor, Process Engineering, Resolution Copper, the plant ground-breaking is not likely for another eight years!

Speaking at the 2020 SME MineXchange Conference & Expo, in Phoenix, Arizona, on Tuesday, Marks revealed the plans for the concentrator at the mine, which when operational could become the largest copper producer in North America.

The project, situated close to the former-operating Magma mine, is currently in the process of deepening Shaft 9 down to a level of 2,086 m deep. The project partners will have spent over $2 billion (Rio Tinto share $1.1 billion) by the end of this year to develop and permit the project, including $302 million of additional expenditure approved earlier in 2019. Marks’ long timeline to groundbreaking is a reflection of the lengthy permitting process the project will have to go through.

Following the shaft deepening – expected to be completed in 2021 – and if the project receives the required approvals, development work for the block cave mine could start to take place.

At the same time as the company is focused on these aspects of the project, Resolution is leveraging the drill core it has obtained to calculate all-important metallurgical information and come up with a preliminary concentrator design.

The project has delineated indicated and inferred resources totalling 1.97 Bt at 1.53% Cu and 0.036% Mo from drilling, so there are many datapoints to draw from when it comes to generating a process flowsheet. It has used 79,000 ft (24,079 m) of core – including 38 full holes and 10 partial holes – 527 grindability samples, 646 rougher/cleaner kinetic tests and three pilot projects to come up with these plans, according to Marks.

Ahead of the concentrator, ore will be crushed underground – possibly with a gyratory crusher – and conveyed underground before being hoisted to surface.

The concentrator looks like having a SAG and ball mill configuration without a pebble mill (at least in the initial stages), plus a large cell bulk flotation circuit with columns for cleaning. It would have a separate float for tailings separation and produce both a copper and molybdenum concentrate.

This has the potential block cave mine producing 120,000 t/d of ore, with plant availability expected to be 92%.

And water consumption and recycling are high on the priority list for the project, with Marks saying the company is trying to reclaim as much water as possible. A tailings thickener is expected at the concentrator itself, with the aim to capture 80-85% of the water used in the process, she said.

Excelsior’s Gunnison ISR copper mine coming to life

Excelsior Mining says it has successfully commenced mining operations at its Gunnison in-situ recovery copper project in southern Arizona, USA.

Following a commissioning program that had been ongoing for several weeks, regulatory approval to commence mining operations through the injection of acid was recently received from the US Environmental Protection Agency.

Delivery of mining fluids to the copper orebody has since commenced with fluids now circulating through a closed-loop system until the concentration of copper held in solution meets sufficient grade to be treated through the Johnson Camp processing facilities. This will lead to extraction of copper and the production of cathode sheets.

Excelsior said first copper cathode sales were expected in the March quarter.

Stephen Twyerould, President & CEO, said: “Following on the heels of the successful completion of the construction phase, mining operations at the Gunnison copper project are now underway. We remain absolutely confident in our capacity to deliver low-cost copper production while maintaining our commitment to safety and the environment.”

Mark J Morabito, Excelsior’s Chairman, said he and the board looked forward to continuing the ramp up of existing operations in 2020 and laying the groundwork for future expansion to Gunnison’s full production capacity of 125 million pounds (56,999 t) of production per year.

Gunnison’s initial capital cost was estimated at $49 million, with the mine expected to produce 2,200 MIb of copper cathode over a 24-year life.

Northern Vertex Mining ready for more gold at Moss mine

Production looks like increasing at Northern Vertex Mining’s recently started up Moss gold-silver mine, in Arizona, USA, as recent modifications to the Merrill Crowe facility and additional output from the heap leach kick in.

The company produced 7,482 oz of gold and 45,876 oz of silver during the three months to the end of June, compared with 6,057 oz of gold and 25,558 oz of silver, marking the company’s strongest quarter to date. In June, alone, Northern Vertex saw 2,580 oz of gold and 18,051 oz of silver come out of the operation.

The Moss open pit and heap leach gold and silver mine hit its commercial straps in September 2018, at which point the company said expected fiscal 2019 production guidance was 36,000-40,000 oz of gold equivalent production.

Northern Vertex said this week that its operations team has made progress in correcting issues that have hampered the process plant since started up, with modifications to the filter press piping, clarifiers and vacuum pump system nearing completion.

“We have observed a large decrease in reagent consumption and an immediate improvement in recoveries of gold and silver from the pregnant solutions,” the company said.

Such improvements to the Merrill Crowe facility recently resulted in the company’s single largest gold shipment to date – of $1.2 million representing nine days of production.

The Moss team initiated a recovery study of the heap leach pad in May 2019, with the purpose to confirm consistent moisture percolation throughout the pad; measure solution volume and solution grade retained in various areas (panels) of the pad, in order to determine the gold and silver inventory remaining on the pad; obtain samples for further bottle roll testing, in order to estimate the amount of gold inventory that can be recovered by re-leach; and design and implement a leach solution application plan to recover additional gold from the leach pad inventory.

Results from the first panel (known as the ‘Central Panel’), which contains approximately 235,000 t of ore have been received, the company said. “Results show remarkable consistency in the percolation of solution, both laterally and vertically. Furthermore, the study confirms there are no dry areas, channelling is not occurring, the pad is retaining its moisture as expected and that the recoverable gold and silver in inventory will meet or exceed feasibility predicted recoveries.”

While the full study, which will include an additional five panels is ongoing, Jim Gubler, Process Manager at Northern Vertex, said the results from the Central Panel indicated there are around 5,000 oz of recoverable gold contained in this area, of which an “estimated 3,000 oz have already been dissolved in the water held in the heap and need only to be flushed and collected”.

He added: “With the leach solution application plan that we have designed, we are projecting that a significant portion of this gold will be recovered over the next several months, which should add to our normal monthly production.”

The ongoing column test program (using crushed ore samples) is predicting ultimate recoveries of approximately 80% for gold and 60% for silver from the heap leach. The column test work on the crusher samples and the heap leach pad recovery study described above will also be used to optimise and shorten the recovery curves going forward, using live ore panels for testing rather than bulk samples that were used in the feasibility, Northern Vertex said.

“Every current test being run indicates that we should be able to outperform the feasibility recovery curves,” the company concluded.

Taseko Mines’s Florence ISR trial copper mine reaches commercial level ahead of time

Taseko Mines says it has reached “commercial grade levels” at its Florence in-situ copper test mine in Arizona, USA, less than six months after well field operations commenced.

The company cannot yet say it is a ‘commercial mine’, but it is well on the way to being able to with permits amendment applications to transfer the test facility into a commercial operation being delivered and financing arrangements being made.

On the former, Taseko said the Aquifer Protection Permit (APP) amendment application for Florence was now on its way to the Arizona Department of Environmental Quality (ADEQ). “The APP is one of two key permit amendments which are required for commercial production at the company’s Florence copper project,” Taseko said, adding that the permit amendment application for the Underground Injection Control Permit will be made to the US Environmental Protection Agency in the coming weeks.

Russell Hallbauer, Chief Executive Officer of Taseko, provided the update on operations at Florence. “This past week, after roughly six months of operating the test facility, the leach solution reached commercial grade levels, well in advance of our anticipated timeframe,” he said.

“Based on previous bench-scale testing, we expected it would take upwards of a year to reach target solution grade, so we are obviously extremely pleased to have achieved this milestone after such a short period of time.”

Hallbauer said the grade of the leach solution coming from Florence’s main recovery well is around 1,600 parts per million (ppm) of copper in solution and would be comparable to a typical open pit, low cost heap leach operation.

“The main difference between Florence Copper and other leach operations is that we have no mining costs associated with our in-situ leach process, making Florence Copper, when in commercial operation, one of the lowest cost operations globally,” he said.

The main focus of the Florence test facility, beyond ensuring the company achieves all the technical targets of its feasibility study, will be building the company’s on-the-ground operational experience to streamline the transition to commercial production, according to Halllbauer.

“Based on the knowledge we have gained in the last six months, the benefits of the two phase approach (production test facility followed by the commercial facility) will significantly improve the ramp up of the final commercial scale operation,” he said.

Stuart McDonald, President of Taseko, said financing for the commercial production facility is progressing with multiple options continuing to be pursued.

“We have initiated discussions with potential lenders and financing partners and we remain on track to have a plan formalised in the coming months,” he said.

“We now have the three key initiatives – technical, permitting and financing – all aligned for our project to be construction-ready in the first half of 2020.”

The commercial Florence mine is expected to produce copper at average operating costs of $1.10/Ib ($2,425/t), come with a capital cost intensity of $5,200/t of copper capacity and yield a pre-tax net present value of $920 million. It also has a slated copper production capacity of 85 MIb/y (38,555 t/y) and a 21-year mine life.