Metallurgical commentary & insights



What's Happening in Gold Ore Processing?

April 2019

Factors driving new developments in gold technology include increasing environmental concern and government regulation over the use of cyanide, the trend towards refractory, complex, and lower grade resources, and the pressure to reduce operating cost and increase plant performance efficiency. Developments reviewed include cyanide alleviation, non-cyanide lixiviants, refractory ores and concentrates, analytical, control and monitoring systems and ore sorting.  Read More


Copper SX Fire Safety - No Grounds for Complacency

August 2018

Based on the proceedings from ALTA 2005 Fire Protection World Summit, which remains an important source of information for the cause, protection and prevention of fires in SX plants.  The proceedings have been republished in the ALTA Free Library for the benefit of the industry, especially newcomers.  Read More


120 Years of Combined PAL Operation for Laterites

April 2017

Ten PAL plants for low grade nickel laterites have been built since the PAL revival started in the 1990s in Western Australia. Eight are operating today. Remarkably, so is their distant ancestor from 1960, Moa Bay in Cuba. This amounts to 120 years of combined PAL operating experience, including 56 years at Moa alone – more than enough to make a realistic assessment.  Read More


Bioleaching Moves into Nickel

February 2017

Bioleaching has finally moved into the treatment of nickel sulphide ore and concentrates, with commercial heap and tank systems now in commercial operation in Finland, and a commercial tank system planned for Western Australia. The projects have undoubtedly benefited from the experience gained in heap bioleaching in the copper industry and tank bioleaching in the gold sector, as well as the downstream processing and product recovery technology applied in nickel laterite pressure acid leaching projects.   Read More


Copper SX-EW - What are the Options?

January 2017

Since it burst onto the world’s metallurgical scene in the late 1960s, copper SX/EW has gone from strength to strength and has seemingly blitzed all comers. But it does have some drawbacks, which opens up opportunities for possible options.  Read More


Uranium Ore Processing Still Advancing

November 2016

Uranium ore processing technology continues to advance, driven by the need to reduce capital and operating costs, the move towards lower grade and more difficult ores, the need to improve the processing of saline leach solutions and the increasingly stringent environmental regulations.  Read More


Developments in Hydromet Processing of Nickel Laterites

October 2016

Efforts to develop lower cost and simpler hydromet alternatives to pressure acid leaching (PAL) for laterites are being made by a number of organizations. Processes retaining sulphuric acid as lixiviant include various atmospheric tank leaching concepts and heap leaching. Atmospheric leaching processes using hydrochloric and nitric acid are also being developed. Meanwhile the number of pressure acid leaching operations is increasing, with some major projects still ramping up towards full production, and by-product scandium operations are being developed.  Read More


Necessity is the Mother of Invention

August 2016

Inventions and innovations in the metallurgical industry often come out of times of need...or sometimes even out of desperation!  Here are some classics from my many years in engineering and consulting.  Read More


Feasibility Studies - Foundation or Fantasy?

August 2016

Feasibility studies are a vital part of the sometimes tortuous path leading from a resource discovery to a profitable operation. Yet they come in all shapes and sizes - cheap or expensive, good or bad, well thought out or “off the cuff”, valuable or valueless - and can be a firm project foundation or a fantasy. Read More


New Players in Copper Concentrates Hydromet

July 2016

Some new players have joined the list of hydromet processes for copper sulphide concentrates. A key driving force is increasing industry concerns in the transporting and smelting of concentrates with high impurity levels, especially arsenic. This has led some to focus on removal of impurities rather than total hydromet processing. Read More


Copper Heap Leach Development - Not as Easy as it Looks

July 2016

Heap leaching has become increasingly popular in the copper industry for treating oxide and secondary sulphide ores, and is now being extended to primary sulphide ores.  If you are thinking about a project, here are some practical pointers to help you towards a successful outcome.  Read More


ALTA 2019 Pressure Acid Leaching *NEW*

May 2019

The main topics discussed included improvements to the HPAL process for laterites, thickening and rheology, indirect heaters, utilising acid in HPAL residue, individual pots versus multi-compartment autoclaves, operation and control improvements, safety, hazardous materials, and tailings disposal, benefits of industry information sharing, HPAL versus NPI for producing nickel and cobalt sulphates, production of MHP versus MSP for supplying the battery industry, future prospects for nitric and chloride atmospheric tank leaching, and effect of nickel price on processing development. Read More


ALTA 2019 Novel Lithium Processes Panel Discussion *NEW*

May 2019

The main topics included Sodium Sulphate Issue, De-Risking the Processing of Non-Spodumene Resources, Outotec Alkaline Leach Process, Stationary Storage Batteries, Alternative LIB Precursor Feed Chemicals, Lithium Iron Phosphate Batteries, Alternative Battery Electrolytes, and Battery Recycling. Read More


ALTA 2019 Developments in Uranium-REE IX Panel Discussion *NEW*

May 2019

The main topics included Future Wish List for IX in Uranium and REE Processing, Standard Procedures for Resin Evaluation, Resin Breakage and Make-Up and the Design of IX Systems, Solvent Impregnated Resins, and IX Versus SX for Uranium Recovery from Phosphoric Acid. Read More


ALTA 2019 Fit-For-Purpose Gold Leaching Systems Panel Discussion *NEW*

May 2019

The main topics included overcoming industry reluctance to adopt alternative lixiviants in gold processing, opportunities for IX in gold processing, advantages of hybrid lixiviant systems, options for replacement of CIP/CIL or RIP/RIL to eliminate inter-stage screens,  extension of thiosulfate to heap and in-situ leaching, and application of cyanide-free glycine leaching to agitated tank leaching. Read More


ALTA 2019 Enhancing ISR Permeability Panel Discussion *NEW*

May 2019

The main topics included, social license to operate hydraulic fracturing, fracturing of hard rock deposits, application of blasting to enhance permeability and create in-ground leaching “silos, and alternative techniques to enhance permeability.  Read More


ALTA 2018 Lithium Processing Panel Discussion 

May 2018

The main topics included lithium market production forecasts, realistic ramp-up times, processing of alternative lithium minerals, testwork issues, novel lithium flowsheets, effect of boron, sodium sulphate issue, lithium carbonate versus lithium hydroxide, and direct shipped ore.  Read More


ALTA 2018 Refractory and Complex Gold Ores Panel Discussion

May 2018

The main topics discussed included the need for new processes for refractory gold ores, alternatives to cyanide, stability of arsenic residues, heap leaching of refractory gold ores, and the need for collaboration and industry research.  Read More


ALTA 2018 Hydromet Processing of Sulphides Panel Discussion

May 2018

The main topics discussed included the future for low-grade ores and concentrates, recovery of iron as a by-product, implications of more stringent water management, impact of logistics on the battery metals product chain, need to understand the market to identify optimum product form, designing processes with flexibility for changing market conditions, prospects for new SX and IX extractants for battery metal purification, and the need and benefits of collaboration.  Read More


ALTA 2017 Pressure Acid Leaching Panel Discussion

May 2017

The main topics discussed were the strategy for a successful HPAL project, the advantages of starting small and expanding later, developing and applying new technology, challenges facing new HPAL projects, effect of nickel price and the largest operation HPAL autoclave.  Read More


ALTA 2017 Lithium Processing Panel Discussion

May 2017

The main topics discussed were the projection of operating costs for new projects, the definition and achievement of battery grade product, assessment of alternatives to lithium, and the cause of battery fires.  Read More


ALTA 2017 Cyanide Alternatives/Alleviation Panel Discussion

May 2017

The discussion focussed mainly on developments in cyanide recovery/recycle technology and non-cyanide alternatives, driven by the need to satisfy the increasing concerns of government regulators and change adverse public perception. Other related topics included on-site manufacture of cyanide, reagents for in-situ leaching, dry stacking of tailings, the potential role of IX, and strategies for funding technological innovations that will be made available to the industry as a whole.  Read More


ALTA 2016 Hydromet Processing of Sulphides Panel Discussion

May 2016

A wide ranging discussion was held involving contributions from the delegates as well as the panel members. The main focus was on whether we are any closer to hydromet overtaking smelting for sulphide concentrates. Read More


ALTA 2016 Membranes in Uranium Ore Processing Panel Discussion

May 2016

The discussion covering the pros and cons of membranes in the hydrometallurgical field and uranium ore processing in particular, including Paladin’s operating experience at Kayelekera in Malawi, and Langer Heinrich in Namibia.
Read More


ALTA 2016 Refractory Gold Forum Panel Discussion

May 2016

A wide-ranging discussion was held involving contributions from delegates as well as panel members. While the main focus was on refractory gold metallurgy, the topics discussed covered all aspects of gold production.  Read More

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