Orway Mineral Consultants (OMC) specialise in all aspects of crushing and grinding modelling, site circuit optimisation, and provide hydrometallurgical expertise. The Australia and Canada-based consultancy is a world leader in comminution, providing a range of services to the mineral processing community. With a primary focus on grinding applications, OMC was instrumental in the wide acceptance of SAG milling in the mining industry.

Comminution

OMC provides crushing and grinding circuit selections and major equipment sizing services for both greenfield and expansion projects. By interpreting rock breakage comminution testwork data and modelling, OMC can determine the most efficient crushing and grinding circuit configuration for all ore types:

• Autogenous/semi-autogenous milling
• SAG and ball milling, recycle crushing
• Secondary/tertiary crushing ball milling
• HPGR ball milling
• Fine grinding
• Rod milling
• Scrubbing

Work is undertaken as part of engineering scoping/pre-feasibility, definitive feasibility studies or detailed design which includes:

• Metallurgical test work specification and supervision
• Comminution circuit modelling and major equipment selection
• Flow sheet selection
• Piping and instrument diagrams
• Mass balances
• Operating costs
• Process design criteria
• Process and engineering design for new and upgrade projects
• Studies and independent reviews

OMC provide exclusive mill sizing services to Outotec.

Grinding circuit optimisations

OMC undertake many grinding circuit optimisations worldwide, providing clients with significant cost savings and increased production levels often requiring no capital input.

Comminution circuit optimisations typically involve circuit audits and collection of circuit data. This includes major equipment sizes and operating conditions. Mass flows, particle size distributions and densities for each stream are collected along with samples for ore characterisation testwork.

Considerable improvements in plant performance are often obtained through recommended changes to control philosophies and training based on preliminary audit results.

Survey data is model fitted using a combination of OMC power based and JKSimMet modelling techniques. Simulations are undertaken to assess influences of varying process parameters on circuit performance. Recommendations are made based upon analysis of data and specific problem areas are identified. These typically include changes to:

• Mill feed size
• Control strategy
• Pulp density
• Recycle crushing
• Cyclone configuration and operation
• Throughput
• Ball load levels
• Liner and grate design
• Circulating load control

Expertise is provided across a wide range of commodities including gold, copper, nickel, iron ore, uranium, manganese, lead/zinc and mineral sands.

Hydrometallurgy services

OMC has fostered a highly skilled team specialising in the field of hydrometallurgy. OMC understand issues in complex hydrometallurgical processing with expertise in a wide range of commodities including: uranium, nickel, copper, cobalt, platinum group metals, gold and safe disposal of metalloids that co-exist.

Services include:

• Sample selection
• Testwork specification and pilot plant supervision
• Modelling and mass balancing
• Studies and design
• Audits/due diligence
• Client/owners team support
• Commissioning

Nickel / Cobalt – OMC has experience in leaching nickel and cobalt from both lateritic and sulphide deposits via atmospheric, pressure oxidation or metathesis process. Leach products can be taken through purification using solvent extraction, precipitation or ion exchange process to crude and pure semi-products, or refined to metals (divided cells for example).

Copper – OMC has experience in leaching copper from low and high grade oxide deposits via heap leaching and tank leaching, sulphide concentrate leaching via low and high temperature pressure oxidation process as well as SXEW or direct EW. OMC are involved in producing super concentrates via concomitant removal of uranium, cobalt, arsenic and other deleterious elements from copper sulphide concentrates.

Platinum Group Metals (PGM) – OMC has design and operating experience in refining, to 4N purity, of platinum group metals and gold. Feed sources are typically concentrates from mattes and secondary feed stocks (e.g. spent autocatalysts).

Processes include classical chloride systems and newer technologies incorporating substituted quaternary ammonia salts (SQAS).
OMC can design to NIOSH/ACGIH air quality standards.

Uranium – Design and operating experience with calcrete, sandstone, granitic and sulphide hosted deposits across the globe. We routinely scope and supervise testwork programs, as well as pilot plant trials, using acid or alkali leaching methods followed by solvent extraction or ion exchange concentration.

OMC assists the International Atomic Energy Agency (IAEA).

General metallurgical services

Flotation

OMC has expertise in base metal and refractory gold ore flotation. Techniques include bulk, differential and collective/selective methods at laboratory, pilot plant and conventional full scale.

Gold metallurgy

OMC has strong gold processing expertise and can provide assistance in all aspects of gold processing including:

• Testwork sample selection representivity and variability
• Specification/supervision of testwork programs to determine optimal extraction conditions
• Gravity gold extraction, intensive cyanidation leaching or gravity finish
• Leach/adsorption circuit specification and operation
• Refractory gold processing
• Desorption circuit specification and operation
• Goldroom operations and smelting
• Auditing, operations reviews
• Cyanide destruction

For more information, please contact OMC.