Copper mining: Driving efficiency to meet the growing demand for clean energy.

Copper Ore Chunk

Society’s plans for a decarbonized world will rely on renewable energy and transport electrification, which is a copper-intensive strategy. Copper mining activities will struggle to meet this growing demand as new copper deposits discovery rates are lagging, and current operating mines are declining. It is estimated that copper mining supply shortfalls could reach ~ 15 million tonnes by 20341

Meeting this demand for copper and other clean energy minerals, against a backdrop of growing operational/environmental constraints, calls for innovations and the adoption of clean technologies.  The mining community, contributing between 4% to 7% of global emissions, has set year 2050 for Net Zero as its target for decarbonization. Meaning that to achieve the 1.5°C climate-change target by 2050, the mining industry will need to reduce direct CO2 emissions to zero. 

At Thermo Fisher Scientific, our solutions include high availability samplers, elemental and particle size analyzers, and bulk weighing and monitoring equipment. Shaped by decades of working with the copper mining industry, this technology enables optimization of mine life and plant feed grade, yield, efficiency, and the profitability of copper mines and concentrators. Ultimately, our technology helps to make clean energy greener.

Decarbonization is not all. However, pressure from investors is growing and the social license to operate is getting harder to negotiate. Copper mines must reduce their environmental footprints and the intensity of water and/or power consumption. Furthermore, the concentration or grade of copper in economically viable deposits is decreasing. 

1 O Da Silva News Item ‘Rio Tinto Copper CEO: Copper Market to See Deficit by 2020s’, April 10th 2018.
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2 S&P Global Platts News Item ‘NET ZERO: Mining faces pressure for net-zero targets as demand rises for clean energy raw materials
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The variable nature of deposits at a micro scale level cannot effectively be captured in block models. To do so would be drilling intensive and very expensive. This can mean in some deposit a high level of heterogeneity either in grade distribution and/or composition that cannot be measured to the bench level. As such, many concentrators face a highly variable feedstock, sometimes on an hourly basis. Material above the cut-off grade may routinely be sent to waste. Conversely, the feed stockpile can too easily drift below the specified cut-off grade.

Bulk ore sensing and sorting enables the preconcentration of the concentrator feed while simultaneously improving its consistency. It sets a foundation for better performance in all subsequent operations delivering dividends by:

  • Increasing resource utilization
  • Adding throughput with no plant expansion
  • Reducing water consumption per T of product
  • Reducing energy consumption per T of product
  • Increasing recovery

For a new greenfield mine, effective ore sorting could mean a smaller milling circuit and overall concentrator layout resulting in lower CAPEX. It could also mean accessing satellite deposits of lower grade more effectively.

For an established plant, estimates suggest that ore sorting can deliver additional profits in the region of $100 million, with no mill expansion3 (based on a 40,000T per day operation).

Bulk ore sorting is reliant on analytical technology that can rapidly differentiate material that is at or below cut-off grade. Analyzer precision and accuracy are equally critical with high penalties for both false acceptance and false rejection. False acceptance negatively impacts the average grade of the feed stockpile or plant feed. False rejection sends recoverable copper to the waste pile resulting in losses. A high spec analyzer solution will minimize the loss of valuable material sent to waste, while routing only economically viable ore into the process.

Learn more about the solutions we have to offer to the copper industry from our ebook.

Why should PGNAA / PFTNA be used in copper mining?

Neutron activation analysis techniques such as Prompt Gamma Neutron Activation Analysis (PGNAA) or Pulsed Fast Thermal Neutral Activation (PFTNA) are well-suited to bulk ore sorting. Bombarding materials with neutrons cause the elements to emit secondary, prompt gamma rays, creating an identifying ‘fingerprint’. PGNAA and PFTNA analyzers penetrate the entire incoming ore stream, ensuring that the whole material stream is analyzed equally and accurately.

Find out more about the Thermo Scientific CB Omni Fusion Online Elemental Analyzer which offers market-leading performance for efficient ore sorting.

Crushing and milling account for just over 50% of copper mine site energy consumption3 making them a primary target for cost reduction. The goal is to grind the ore just enough for optimum copper mineral liberation in the froth flotation plant circuit. Under-grinding reduces recovery; overgrinding reduces throughput and wastes energy.

Real-time particle size analysis in slurry is the key to effective grinding control in finer particle sizes prior to froth flotation. It provides immediate feedback of how the grinding circuit is performing to provide a secure foundation for responsive control, manual or automatic. Online particle size analysis provides the real-time measurement required, with minimal manual effort, and makes it possible to:

  • Optimize energy consumption per T and mill throughput
  • Maximize copper recovery and liberation
  • Instantly detect process upsets in the grinding circuit
  • Implement automated and feed forward mill advanced control
  • Reduce grinding media consumption and liners wear
Grinding control chart
Grinding just enough is critical – too much, means lower throughput and/or higher energy consumption, too little and recovery suffers.

Why use ultrasonic attenuation?

Ultrasonic attenuation is a particle size measurement technique well-suited to the concentrated slurries associated with mining applications. Particles subject to ultrasound waves dampen or attenuate transmission to an extent that correlates with particle size. Ultrasonic detectors are directionally dependent, eliminating issues with multiple scattering so even high percentage solids slurries are measurable without dilution. Find out more about the Thermo Scientific PSM 500 Particle Size Analyzer which uses this technique to deliver high availability, real-time, in-stream particle size and slurry density measurement.

3 CEEC Factsheet – Energy consumed in comminution

Reagents such as collectors, frothers, and pH modifiers are essential in copper mining workflows to maximize copper recovery in the froth flotation circuit. They improve separability, stabilize air bubbles, and enhance separation selectivity. But optimization of this complex process and chemistry is often empirical, with operators overly reliant on experience. Elemental analysis, in combination with particle size data, provides a foundation for the development of better process understanding. It supports the efficient manipulation of process parameters such as aeration rate and pulp level in response to changes in, for example, ore minerology, feed rate, pulp density and particle size. Optimizing control of the flotation circuit makes it possible to:

  • Reduce reagent consumption
  • Quickly detect changes in the feed material, or process upsets
  • Ensure target concentrate quality
  • Track copper, as well as other valuable and deleterious elements to assess process performance and maximize recovery.

XRF and PGNAA: The key to measuring more elements of interest

X-Ray fluorescence (XRF) is an effective analysis technique for copper and other battery elements effectively measuring all elements from sodium through to uranium on the periodic table. Our instream XRF analyzers; AnStat-330 and MSA-330 have the reputation for delivering a higher availability than any other system on the market. However, XRF cannot directly measure lighter elements such as Na, Mg, Al, Si which can often be elements of interest in base metals. The Thermo Scientific GS Omni Light Element PGNAA Analyzer is designed to measure lighter elements in copper slurries, such as sulfur, in real-time for particles up to 5mm in diameter.

PGNAA Detection Periodic Table

Concentrate quality defines its market price and its NSR (Net Smelter Return). Copper content or grade is critical and typically lies in the range 25 – 35%. But smelters impose penalties for impurities such as arsenic because of their detrimental impact on the smelting process.

Online elemental analysis delivers real-time product quality control providing the information required to:

  • Manage product quality /grade impurity levels
  • Only ship concentrate that meets impurity level specifications
  • Maintain a consistent, premium concentrate product
  • Maximize revenues or Net Smelter Returns (NSR)
  • Safeguard and enhance reputation
  • Reduce smelters and refineries emissions and byproduct by minimizing recovery of impurities

Find out more about our range of XRF and PGNAA analyzers:

Products

Frequently asked questions

Yes, our team of plant design engineers that can help design a solution around your space constraints. Utilizing integrated products that deliver two functions within the footprint of 1 product is the key to this, alongside of dedicated analyzers with small footprint and low head loss.

Dedicated analyzers can be placed close to the sample point to minimize the need for additional piping and often avoids the need for a pump. The Thermo Scientific AnStat-330 Sampling and Analysis Station is a dedicated analyzer that also incorporates an industry leading statistically representative sampling station. It has the lowest head loss of any analyzer on the market which enables its placement downstream of the sample point thereby using gravity to take the sample to the analyzer.

The Thermo Scientific GS Omni Light Element PGNAA Analyzer can measure up to 8 streams and is designed to measure light elements that XRF cannot measure. Combined with a Thermo Scientific XRF analyzer, our online elemental analyzer portfolio allows customers to measure a broader range of elements than any other competitor product on the market.

Thermo Scientific samplers and analyzers have the lowest head loss on the market. This helps minimizing the need for additional piping and pumps. Our solutions can help reduce costs of new plants by sensing and sorting waste and ore prior to stockpiles and plant feed. This diversion of below cut-off grade ore and waste enables a smaller plant footprint.

Yes, with a new site you have a one-off opportunity to integrate analysis and more specifically sampling from the outset. To make the most of this opportunity start considering sampling and analysis early in the design process, not towards the end, as an add on. A defining advantage of our samplers is low head. By delivering multiple sampling stages at one floor level, they can lower plant elevations and eliminate any need for sampling towers. This can have a major impact on construction costs.

Yes, and it could be significant. First, let’s assume all streams are analyzed as intended. Cycling around each stream takes time and the frequency of measurement is therefore lower than with a dedicated analyzer. Each additional stream means a longer time between measurements. For some applications this isn’t a problem, a measurement every 15 minutes may be sufficient. However, for greater process control and benefit from real-time continuous measurement, the Thermo Scientific AnStat-330 Sampling and Analysis Station combines representative sampling and elemental analysis into one product.

However, the second challenge comes from routing several streams to a single location. In a sizeable plant, this often involves large pumps, pumping slurry through long sections of pipes, creating risks such as pipe blockage or pump failure. Analyzers measuring 20 streams could be reduced to 4 or 5 streams only after a few months of operation because of the reduced availability of each lines from blockages. Slurries density and viscosity often makes it a product difficult to transport and sample representatively. Using dedicated analyzers on critical streams and then strategically placing multi stream analyzers to measure between 3 and 12 streams typically provides a good balance between cost, analysis intervals and uptime.

Integrate the two into one product. Placing the analyzer within the sampler eliminates any scope for settling or sedimentation. This approach ensures dedicated real-time measurement with minimal risk of blockage. On the CAPEX front, this approach reduces piping design hours and expenditures on pumping. On an ongoing basis, integration minimizes maintenance and operation costs. The off-the-shelf solution, Thermo Scientific AnStat-330 Sampling and Analysis Station, encapsulates this approach. As a low head loss system, it offers market-leading availability and is well-matched to applications requiring high frequency dedicated measurement.

The benefits of ore sorting against a backdrop falling ore grades are difficult to argue. However, ore sorting projects can be associated with considerable CAPEX. Most of the costs is in material handling with diverting, routing, conveying and transport since once sensed, the ore is “sorted” meaning diverted to a waste stream. However, the return on investment on the capital and operating costs will rely on the ability of an analyzer to differentiate the incoming material. The difference in return from even a marginal difference in performance is make or break in this application.

Although bulk and particle sensing and ore sorting is not a new technology, it has been slowly adopted by the mining industry. As pioneers in the field of neutron activation analysis - Prompt Gamma Neutron Activation Analysis (PGNAA) and Pulsed Fast Thermal Neutral Activation (PFTNA) - we understand its strengths, its limitations and how best to implement it. Not all PGNAA/PFTNA technology is equally powerful, and some is not adequate. Source strength, detector quality, and system design all play a role in determining performance and it pays to understand how. For example, measurement uniformity, across the entire incoming ore stream is vital and not feasible with systems with just a single central detector. In summary, the analyzer you choose for ore sorting is critical so consider the options carefully and get advice. And do the maths. Look at the performance on offer and see what it might mean in terms of the bottom line. You’ll find an example of this type of calculation in our ebook

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