Most hard rock ore bodies will need a wet grinding stage during piloting to facilitate mineral liberation prior to downstream processing. As the required milling particle size distributions (PSDs) do not conveniently scale down to suit small scale processing, matching the mill size and type with the appropriate media charge to achieve the required mass throughput cannot be taken for granted in pilot plant operations. The same applies for the integrated mill product classification circuit (i.e. screening or hydro-cyclone). ALS has an extensive pilot grinding capability together with years of experience in operational techniques to bring the pilot milling circuit into equilibrium as soon as possible, thereby maximising precious sample mass for downstream operations.
Every pilot plant project will have different requirements insofar as sample characteristics,
throughput, and feed and product PSDs, which results in a different grinding circuit almost every
time. Thus, achieving the correct pilot grinding solution requires a large equipment inventory
together with a flexible approach and requisite expertise to build and operate the plant. The
main factors involved are outlined below:
Grinding mills: There is no one size fits all when it comes to grinding and many different mills are required to achieve a range of applications. Broadly, ALS holds the following pilot mill types and sizes in inventory:
Feed arrangements & slurry handling: No mill can operate without the appropriate before
and after materials handling arrangements. ALS has a range of different sized feed hoppers
and belt/screw feeders to match the mill size. Similarly, a range of slurry pumps in various sizes
is available to handle mill slurry product including: Open bowl Sala and Metso pumps, Warman
AH Slurry pumps, Bredle peristaltic hose pumps and Sandpiper peristaltic diaphragm pumps. In
combination, the above equipment can meet most grinding solutions.
Classification systems: Closed circuit classification to emulate industrial scale practice is imperative for pilot scale operations. Typically, this falls into two main categories:
ALS can meet your needs and can also leverage off vendors for specific or non-conventional equipment items.
Please contact us for further details.
We can build bespoke circuits to handle between 30 kg/h up to 4 tph. The maximum feed rate is not so much the mill rather than the limitations of downstream materials handling (i.e. thickening and filtering).
Yes, ALS has a large grinding media inventory, but clients are welcome to source their own supplies and have it delivered to the laboratory.
As little as 3 hours operation in most cases, but challenging circumstances often arise which may take longer.
Tentatively yes, depending on the scope of work. Contact us to discuss.
Generally, no. We need our mills at our labs and hire is not our core business.
Yes, but caveats apply. Batch hydro-cyclone testwork comes with many challenges not seen in continuous industrial plants. This is mainly concerned with settling and particle stratification in the feed tank, which can skew PSD results. Contact us to discuss.
No, but hire units are available.
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.
Grinding always precedes other processes, both at bench scale and pilot scale that may include:
Click on the above links or contact us for further information. We can integrate a full program for you if required.