Dump and heap leaching (via irrigation and percolation of cyanide onto and through the material) is often the selected process option for many marginal low-grade orebodies or pre-existing waste/tailings dumps. In 2021 ALS has expanded into a new bespoke column leaching facility that offers a full range of heap and dump leaching services, covering basic scoping tests through to feasibility studies on larger scale continuous columns.
In place of heaps and dumps, laboratory testing is ultimately conducted in columns of various sizes. Column leaching using cyanide solution to assess heap-leaching potential of gold bearing ores usually follows the following processes:
An important consideration in laboratory test programs is that the prepared samples have a size distribution that approximates a commercial crushing plant output for the desired top-size. This may require appropriate adjustment of the primary crushed product to avoid a disproportionate distribution in the coarse-end sizing.
ALS has also conducted sequential column tests whereby leach solution from one column is used to irrigate a second column in series. Loaded leach solutions can be passed through activated carbon columns and the regenerated cyanide solution recycled.
ALS understands that every gold program needs a tailored testing flowsheet specific to the ore.
Please contact us for further details.
This will depend on the number of tests required and the column dimensions. Typical column and mass requirement are tabulated below:
|Max. Ore Height (m)
|Approx Mass per m Height (kg)
|Max. Crush Size (mm)
Generally, yes. ALS has facilities and procedures to treat fibrous and radioactive samples. Surcharges do apply, however, to cover safety equipment, monitoring and decontamination.
ALS is a quarantine approved premises and treats many samples of oversea origin. Strict regulatory requirements are in needed around packaging and paperwork, however. ALS can advise you on these requirements.
Generally, no. Insurance and safety protocols typically prevent renting laboratory space and this is not part of ALS’s business model. Clients are able to visit and witness testwork but this is to observe only. Typically, clients may attend on 24/7 piloting campaigns and interact with senior staff members for technical and operational issues.
Yes, clients are always welcome to visit our facilities and observe samples or tests in progress. Inductions are required and other rules may apply to visitors.
Yes, if a testwork program is in progress, ALS will happily dispatch testwork products and feed samples to vendors, third party laboratories, and customers as required. Fees apply.
No, as it is not our core business and would put us in direct competition with many of our clients. We can, however, put you in contact with a range of reputable engineering providers and consultants.
Gold ores and the associated free milling metallurgical testwork results very often don’t fit into nice categories and packages and will often require other testwork, such as:
Click on the above links or contact us for further information. We can integrate a full program for you if required.