Tag Archives: Arizona

Heap leach operations edge closer at Bonanza Harquahala gold mine

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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

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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

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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

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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

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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

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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.

Bingham Equipment receives Hard-Line distribution rights in Arizona

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Hard-Line says it has signed up Bingham Equipment Company as the company’s newest distributor in Arizona, USA.

With 11 locations in Arizona, Bingham Equipment will distribute Hard-Line’s LP401, MT52, and the RRC.

The LP401 (pictured) is a remote control operated low profile loader (skid steer) that can be used in a variety of restrictive areas where a normal man-operated machine cannot operate, Hard-Line said. The MT52 is a mini track loader that can “dig, trench, move materials and reach small, tight spots”, while the RRC is a versatile radio remote control that can operate any machine, make and model and is designed to be used in rugged and harsh environments, the company said.

Chad Rhude, Hard-Line’s Vice President, US Operations, said: “We are excited to be working with a great partner like Bingham Equipment Company. With their excellent reputation and many locations throughout the state of Arizona, it gives us a local presence for sales and support of our LP401 product line.

“We look forward to working with Bingham to showcase the versatility and capability of the LP401 in delivering a low-profile, fully-remote controlled machine platform to enhance safety and productivity in the municipal, construction and agriculture sectors in Arizona.”

Rosemont now a ‘fully-permitted, shovel-ready copper project’, Hudbay says

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Hudbay Minerals says it has received the approved Mine Plan of Operations (MPO) for the Rosemont copper project from the US Forest Service.

This completes the required permitting process for the project given Hudbay received the Section 404 Water Permit earlier this month.

Alan Hair, Hudbay’s President and CEO, said: “With the receipt of the Section 404 Water Permit, an agreement to consolidate 100% ownership and receipt of the approved MPO, Hudbay continues to move the project forward.

“Rosemont is now a fully-permitted, shovel-ready copper project and we look forward to developing this world-class asset.”

Rosemont, some 48 km southeast of Tucson, Arizona, is one of the world’s largest undeveloped copper projects. A 2017 feasibility study showed Rosemont could produce 112,000 tons (101,605 t) of copper over its life of mine and, based on a $3/Ib copper price, deliver a 15.5% after-tax unlevered internal rate of return.

Hudbay’s Rosemont copper project moves forward with 404 Water Permit

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The US Army Corps of Engineers has issued a Section 404 Water Permit for Hudbay Minerals’ Rosemont copper project in the US, the mining company says.

Rosemont has already received the Final Record of Decision from the US Forest Service (USFS), a process that involved 17 co-operating agencies at various levels of government, 16 hearings, over 1,000 studies, and 245 days of public comment resulting in more than 43,000 comments.

The company said: “Now that the 404 permit has been issued, Hudbay expects to receive Rosemont’s Mine Plan of Operations from the USFS shortly and looks forward to moving the project into development.”

Rosemont, around 48 km southeast of Tucson, Arizona, is envisaged as an open-pit mine producing copper, molybdenum and silver. It is expected to have an annual average life of mine copper production of 112,000 tons (101,605 t).

The Rosemont site will include a processing plant and associated facilities, transmission lines for power and water, the pit, and waste rock and dry-stack tailings storage facilities.

“Best available demonstrated control technologies will be the hallmark of Rosemont,” Hudbay said. “These technologies will contribute to maximising production while minimising environmental impact. At Rosemont, this will include the use of dry-stack tailings – a technology that significantly reduces water use and improves reclamation – along with leading-edge lighting designs to maintain dark skies, solar energy as a source of power, dust collectors with cartridge filters and trucks with Tier 4 engines to ensure compliance with air quality standards.”

Alan Hair, Hudbay’s President and CEO, said: “The receipt of Rosemont’s 404 Water Permit is a major milestone in our efforts to build a modern mine that will fulfil the requirements of its permits, create jobs and provide benefits for all of our stakeholders.

“We appreciate the diligence that the Army Corps has put into its consideration of Rosemont’s permit application, and look forward to advancing Rosemont into construction.”

Hudbay said it would continue to execute its plan regarding the Rosemont project and provide updates as developments warrant.

Resolution Copper ready to sink to new depths in Arizona

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Resolution Copper says, after completing the two-year-long rehabilitation phase of the underground mine, in Arizona, it is ready to move to the deepening phase of what could end up being one of the biggest copper mines in the world

Resolution, owned 55:45 by Rio Tinto and BHP, is the owner of the massive Resolution copper project.

In a project update, the company said the proposed mine continued to make progress on all fronts.

“Resolution Copper recently reached a key milestone in its development, with other critical work on track for completion in the near future,” the company said.

Work is progressing on schedule to deepen the historic No 9 shaft, originally constructed in 1971, according to the company. The project scope consists of rehabilitating the shaft, sinking it to approximately 2,086 m and linking it with the newer No 10 shaft completed in 2014.

The rehabilitation phase was completed in December 2018 after approximately two years, and the deepening phase will require another two years, commencing in the June quarter of 2019, according to Resolution. This would see the deepening phase completed in early 2021.

“Connecting the shafts will enhance safety and establish the basis for developing towards the copper deposit,” Resolution said. “The shaft connection will provide a second egress route between the two shafts and improve ventilation.”

The No 9 shaft deepening project has made significant achievements over the last three months, according to the company.

“Following successful cleanup of the existing shaft bottom in December 2018, the shaft crew proceeded to outfit the 4,000-ft (1,219-m) level with a bulk air cooler that will chill the intake air for the No 9 shaft sinking,” Resolution said.

“The crews sinking the shaft use a Galloway work stage (pictured), which allows the miners to do their work with a high degree of automation, withdraw during the blast, and then quickly return to the bottom and repeat the cycle.”

The five-deck work stage has four jumbo drills, two shaft mucking machines, a concrete pouring system, and all the tools needed to advance the utilities (pipelines, electricity, etc). The Galloway used to complete the shaft rehabilitation was also removed from the shaft to make room for the sinking Galloway, which is specially designed to support the deepening work, according to Resolution.

“Removal and installation of these Galloways involved technically complex lifts with multiple steps that were well planned for safe and efficient execution,” the company said.

Another significant achievement was the successful phase-1 commissioning and testing of the emergency generator system, Resolution said.

“In the event of a site power outage, the addition of these generators provides the ability to operate the auxiliary hoists for both No. 10 and No. 9 shafts and to restart the necessary refrigeration, ventilation and pumping to maintain the infrastructure at Temporary Pump Level 2,” Resolution said.

Looking forward, the project will focus on surface setup and shaft services work to support the sinking, completing the infrastructure installation on the 4,000 level, which is underway, and finishing the Oak Flat substation transformer upgrade, Resolution said.

The proposed underground block cave mine at Resolution is expected to become the largest copper mine in North America, capable of producing nearly 25% of US copper demand each year. As at Codelco El Teniente, the mining method will be panel caving, which allows for the mining of very large relatively low-grade underground orebodies by dividing the deposit into smaller strips, or panels, so that the ore can be removed in a safe and efficient manner.

Ore production from the underground operations will be a nominal 120,000 t/d after an extensive construction and ramp-up period. The maximum throughput will be approximately 150,000 t/d. Ore will be crushed underground and then transported by conveyor to two production shafts and hoisted to an underground midway offloading station within the two production shafts.

Resolution Copper will use a standard-gauge rail system that will allow bottom-dump railcars to be gravity-loaded with ore delivered from overhead chutes, according to the company. These railcars will be routed to the dump station above the underground crushing facilities. Resolution Copper will use electric semi-autonomous locomotives to pull the railcars. The rail system will be a looped configuration, with two parallel drifts spaced on approximately 18 m centres in the production areas.

In total, approximately 594 pieces of mobile equipment are expected to be employed, which includes the large LHD fleet for the extraction level, moving ore from the drawpoints to the ore passes.

The mine is expected to reach depths of up to 2,100 m and temperatures in excess of 70°C. Last year, Rob Atkinson, former Head of Productivity & Technical Support for Rio’s G&I team, said operating at such a depth meant it really had to be “a fully autonomous mine”.