Tag Archives: water treatment

Clean TeQ DESALX plant up and running at Kirkland Lake’s Fosterville gold mine

Clean TeQ Holdings Limited has formally handed over a Continuous Ion Exchange Desalination (DESALX®) plant to Kirkland Lake Gold’s Fosterville gold mine in Victoria, Australia.

Clean TeQ says it was engaged to design, supply and commission a two million litre-per-day Clean TeQ DESALX mine water treatment plant, with the plant designed to deliver a sustainable water management solution by treating mine process water.

The plant construction was completed in late 2019, with commissioning and operations commencing in early 2020. Now, Clean TeQ has confirmed the plant has passed the performance tests specified in the engineering, procurement and construction contract and the customer has issued a formal notice of acceptance and completion, it said.

Sam Riggall, Clean TeQ CEO, said: “After successfully demonstrating the world’s first ever commercial scale CIF plant in Oman late last year, this is yet another moment of great significance for Clean TeQ.

“Confirmation of the successful deployment of our innovative DESALX solution for this application, designed and delivered by Clean TeQ, is strong validation of our proprietary continuous ion exchange technology, and provides us with a firm foothold in the mining waste water treatment market from which we can continue to grow the business.”

The DESALX technology consists of two continuous ionic filtration (CIF®) modules in series removing divalent cations and anions present in the water through complementary processes. The modules contain ion exchange resins that are cycled between columns using air lifts, allowing for continuous operation and regeneration of the system. This system increases impurity removal efficiency, reduces chemical use, and provides protection against fouling, according to Clean TeQ.

The DESALX solution is well suited to purification of difficult to treat waste waters with high hardness, sulphate, and heavy metals as well as suspended solids which can foul reverse osmosis membranes. These types of waste waters are common in the mining industry, including acid mine drainage water, the company explained.

At Fosterville, the equipment provided by Clean TeQ includes a precipitation package to remove antimony and arsenic. The effluent from the clarifiers is treated by the DESALX plant to remove sulphate, calcium and magnesium with gypsum as the only by-product. The DESALX effluent is then further treated by reverse osmosis to produce water for re-use.

“The Clean TeQ system is a key enabling component of the customer’s overall water management strategy which includes a medium-term target of creating a true ‘zero liquid discharge’ solution that does not produce any saline brine and includes aquifer reinjection,” Clean TeQ said.

Clean TeQ Water is now focused on completing one additional key project at a copper-cobalt mine in the Democratic Republic of the Congo, and a number of pilot programs in China.

“This Clean TeQ system, as well as the plants recently completed in Oman and Australia, are the first of their type anywhere in the world and have been deployed as part of three different technical solutions,” the company said. “The successful delivery and commissioning of these plants provides strong demonstration of the efficacy of Clean TeQ’s suite of proprietary ion exchange technologies and their versatility for metal extraction and wastewater treatment. As commercial scale plants, the facilities provide a valuable platform from which to now rapidly grow Clean TeQ Water.”

BQE Water to manage and treat water at El Mirador copper-gold mine

BQE Water has signed two agreements with EcuaCorriente SA (ECSA), an Ecuador subsidiary of a Chinese consortium, to prepare an adaptive mine water management plan and to improve the design of an existing water treatment plant for the El Mirador mine the consortium owns and operates in south-eastern Ecuador.

The first contract is for an assessment of the water treatment plant and a water management plan that is adaptive over the life of the mine based on water flow and quality that will be monitored as part of the plan.

Added to this is a second contract to provide technical support for implementing immediate improvements in the engineering design and operation of the existing water treatment facility to increase its robustness and reduce both project risks and long-term operating costs, BQE said.

Qiaofeng Xu, the Project Director for ECSA, said: “We selected BQE Water for their unique technical expertise, their successful track record in the design and operation of large water treatment plants for major Chinese mining producers, and for their ability to support project execution utilising personnel from their South American, China and Canadian offices.”

Songlin Ye, Vice President for Asia at BQE Water, said: “Our ability to do business with large Chinese metal producers and the success of our water treatment operations in China were instrumental in securing these new contracts. The El Mirador project is significant for BQE Water as it showcases our unique strength to be a trusted water services provider for mining projects with Chinese interests at a time when Chinese investment in global mining projects can be expected to grow.”

Oscar Lopez, General Manager for Latin America at BQE Water, said the El Mirador project represents the first large mining project where the company will be the technical lead for the overall site water management plan rather than focus only on water treatment.

“And, with the long time horizon for water treatment at El Mirador, the current contracts may provide an opportunity for further cooperation between our two companies to support EcuaCorriente to reduce life cycle costs and conduct mining operations in an environmentally friendly manner at El Mirador,” Lopez said.

The El Mirador mine, owned by a consortium consisting of China Railway Construction Corporation and Tonglin Nonferrous Metals Group, is a large copper-gold porphyry project that was brought into production in 2019. It is expected to produce an average over 200 MIb (90,718 t) of copper and 60,000 oz of gold annually for the next 30 years.

The project site is located in a net positive water balance environment and will require ECSA to treat and discharge mine water into the environment throughout the project life, BQE said. “As production ramps-up and the mine footprint increases, both the volume of water requiring treatment and the water composition will change.”

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

BQE Water to install Selen-IX water treatment plant at US mine

BQE Water says it has entered into an engineering services agreement with Black & Veatch, an international engineering firm, for the design of a Selen-IX™ water treatment plant destined for a mine in the US.

The plant, at a scale larger than the currently constructed 6,400 m3/d Selen-IX treatment plant at Centerra Gold’s Kemess mine site in British Columbia, Canada, will remove selenium below three parts per billion limit at the end-of-pipe, the company said.

The plant will be designed to treat several thousand litres per minute of water on average and to adjust quickly to adapt to the changes in feed flow, according to BQE.

Jim Spenceley, VP Mining for Black & Veatch, said: “We recognise the value of BQE Water’s expertise in water treatment and the uniqueness of Selen-IX, which moves selenium control in the mining industry to a new level and enables important resource projects to be developed.

“The technological leadership of BQE Water, combined with Black & Veatch’s successful track record in delivering mission critical capital projects, matches perfectly the project requirements and we are excited to initiate the work jointly with BQE Water.”

David Kratochvil, President & CEO of BQE Water, said the ability of Selen-IX to remove selenium to levels below three parts per billion, coupled with the ability to quickly adapt to treatment requirements by fast turn-up and turn-down in terms of throughput, was key to signing this agreement.

“It also provides a platform for BQE Water and Black & Veatch to demonstrate to the mining industry our joint capabilities of delivering innovative water treatment solutions safely and cost effectively,” he added.

BQE Water successfully completed lab testing in 2019 that demonstrated the capability of Selen-IX to achieve the required water quality. The design of the water treatment plant is expected to be completed in the September quarter.

Selen-IX is a water treatment process technology that combines ion exchange and electro-reduction to remove selenium from large volumes of wastewater. As a purely physico-chemical process, it is insensitive to water temperature and is highly adaptable to variability in water flows and selenium levels, according to BQE Water. “The process fixes selenium into stable refractory non-hazardous solids suitable for co-disposal with tailings and potential offtake by steel producers,” the company said.

Goldcorp’s Éléonore gold mine cleans up its act with novel wastewater treatment

The latest winner of Goldcorp’s Global Excellence Awards 2019 to be featured in its online blog is the Éléonore gold mine and a novel system that proved its worth removing ammonia and residual cyanide by-products at the company’s Éléonore gold mine in Quebec, Canada.

Goldcorp said: “For any mining operation, effective wastewater treatment to remove contaminants is an indispensable step needed to minimise environmental impacts and maintain the mine’s social license to operate.

“When elevated concentrations of ammonia and residual cyanide by-products were detected in mill effluent at Éléonore, in 2014, the mill and environmental team took decisive action by introducing a novel wastewater treatment process that rectified the problem and secured Éléonore a Global Excellence Award for Sustainability Stewardship.”

Following Éléonore’s mill start-up in 2014, the new process water bleed (discharge) to water treatment plant (WTP) and paste backfill process resulted in increased concentrations of contaminants in water effluent, according to Goldcorp.

Even though the cause of the ammonia and residual cyanide toxicity couldn’t readily be identified, the Éléonore team immediately notified all major stakeholders, such as the Quebec Environment Ministry, Environment Canada and the Cree Nation Government – Environment Committee of Opinagow Collaboration Agreement, informing them on the extent of the problem and plans to rectify the situation.

France Trépanier, Environmental Coordinator at Goldcorp, said: “From the outset, we wanted to be very open and transparent with key stakeholders on steps we were taking to identify the source of the toxicity and plans to resolve the problem. Through ongoing dialogue and regular reporting, we were able to maintain a collaborative climate and establish strong partnerships based on mutual trust.”

During 2015 and 2016, the Éléonore team developed an action plan, investigated various water treatment options, and executed a series of projects including cyanide detox and leaching circuits optimisation to reduce effluent contamination, the company said.

The team also worked on mill water balance through its zero-bleed project with the objective of reducing contaminant process water discharge to the WTP, which involved reducing fresh water consumption by replacing water-sealed pumps used in the mill with mechanical seal pumps. “These projects increased control of process water contaminant concentration but didn’t resolve toxicity issues,” Goldcorp said.

A consultant working on the toxicity problem recommended the Éléonore team consider zeolite treatment and a Moving Bed Bacteria Reactor (MBBR) system to process wastewater effluent. Zeolite is a mineral well known for its ability to absorb a variety of heavy metals and ammonia. MBBR, more commonly used for municipal water treatment, is an activated bacteria aeration system, where bacteria collected on porous plastic carriers breaks down organic matter from wastewater, according to Goldcorp.

A pilot project found that zeolite treatment removed ammonia but did not eliminate the toxicity. MBBR, on the other hand, could remove ammonia and cyanide by-products delivering non-toxic results at low water temperatures (8°C).

In Spring 2016, the Quebec government granted approval for Éléonore to expand its water treatment plant by adding MBBR treatment while continuing to reduce its process water discharge to reach a zero-bleed operation.

Construction got underway in the fall of 2016, and the MBBR treatment plant was commissioned in May 2017.

“Energy efficiency was one of the critical plant design considerations to minimise heating requirements in winter,” Goldcorp said. “The addition of a heat exchange system and an insulated water circuit ensured that process water could feed the MBBR to keep the bacteria-activated treatment as stable as possible during cold winter months. Now, at the second winter, treatment is achieved without any heating at a temperature around 5°C.”

From concept to completion, Éléonore workers were kept up to date on the project’s progress through regular on-site presentations and stakeholders informed of the mine’s plans through monthly reports, quarterly presentations and site visits, the company said.

Trépanier said: “Consistent communication really enabled us to demonstrate how serious we were about solving this problem, which was essential in helping secure support for this project among stakeholders and regulators.”

Following the MBBR ramp up, Éléonore reduced ammonia and cyanide by-product concentrations in its effluent by more than 90% and was designated 100% in compliance with water quality regulations in October 2017. Since MBBR has been in steady operation, mandatory effluent sampling frequency returned from weekly to monthly.

The Éléonore team recently shared its experience in implementing this novel water treatment technology at a symposium on mining and the environment. Since then, it has received numerous enquiries from other mining companies and have hosted site visits to demonstrate the water treatment process, according to Goldcorp.

“There was a lot of people from different departments working on this project over the last two-and-a-half years,” Trépanier said. “It’s very gratifying to be recognised both externally and by our peers at Goldcorp for a successful outcome. We’re very happy to share what we’ve learned with other mining companies to help improve the industry’s environmental performance.”