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SGS is a world leader in hydrometallurgical testing and flowsheet development.


Our team of metallurgists, chemists and engineers are backed by the SGS global network. We offer batch and pilot plant testing and flowsheet development for ambient leaching, pressure leaching and high pressure autoclave recovery systems.

SGS metallurgists are experienced in options for gold leaching, nickel laterite leaching and uranium leaching along with options for other base metals and refractory ores. Our reputation as a provider of bankable flowsheets and testing provides confidence that the metal recovery rates in your full sized plant are optimized.

We have the expertise and the equipment inventory to understand complex orebodies and develop a recovery system that is efficient, safe and cost-effective. SGS leaching services include:

  • Initial batch testing and mineralogy
  • Analysis of variability in the orebody and possible recovery rates
  • Pilot plant and “mini-mine” design and construction in our facilities
  • Ensured compliance with health and safety regulations
  • Fine tuning of pilot plant and mini-mine using 50-100T of ore over a 4 – 6 month period
  • Assistance with commissioning of full sized plant
  • Staff training and ongoing optimization of plant

When choosing a leaching procedure, our experts take many factors into consideration. These factors include the type of metal being recovered, the mineralogy of the ore, grain size, and characteristics of encapsulation; whether the ore is refractory; and the presence of complicating minerals such as chalocopyrite. We also take expected recovery rates and cost restraints into account. Based on these considerations, SGS teams conduct testing of one or more of the technologies that we offer.

Pressure leaching, high pressure leaching and pressure oxidation are conducted in an autoclave at carefully controlled temperatures and pressures. These technologies involve a large capital investment and higher operating costs, but yield high recovery rates from difficult, complex or refractory ores. Advantages and limitations include:

Pressure Oxidation (POX)
Advantages Limitations
  • Highly effective for difficult and complex copper ores
  • Very complex chemistry 
  • High capital costs

Hi Pressure Acid Leach (HiPal)
Nickel laterite, Uranium, Copper, Cobalt
Advantages Limitations
  • High recovery rates
  • Automatic, fully integrated, continuous operation of the system
  • Major capital investment
  • Safety issues must be considered

PLATSOL SGS trademark technology
Gold and Platinum Group Metals (PGM)
Advantages Limitation
  • Low capital costs
  • Suitable for lean concentrates, dirty concentrates and those containing high concentrations of chromium and magnesium
Only effective for precious metals and PGMs

Ambient leaching, including bulk leaching, is conducted in simple heaps, vats or columns. The procedures are conducted at ambient temperatures and pressures. Advantages to these systems include simpler chemistry and operating procedures, and lower initial and ongoing costs. Ambient leaching is suitable for simple ores or those with lower expected recovery rates. SGS ambient leaching systems include:

Bacterial Leaching (Including ACTIVOX, BIOX, GEOCOAT)
Gold, Base Metals
Advantages Limitations
  • Simple technology
  • Improved environmental footprint
  • Effective in a range of temperatures
  • Ineffective for chalcopyrite

SGS also conducts sequential leaching, a diagnostic tool for hydrometallurgical processes:

Sequential Leaching
Advantages Limitations
  • Used to identify different mineral zones in ore deposits
  • Effective for complex copper mineralogy
  • Complex chemistry
  • Procedural parameters must be carefully controlled and monitored

Choosing the most appropriate leaching technology has a major impact on your construction and operating costs and eventual recovery rates. SGS works with you to ensure that your decision optimizes the recovery operation and improves your bottom line.