Macrodiamond Recovery using Dense Media Separation (DMS) Plant
The plant was designed and constructed by Dowding, Reynard and Associates of South Africa and is designed for both the mini-bulk testing of kimberlites and the processing of individual small samples. This plant is ideal for audit samples using either a 150mm or a 100mm cyclone to extract the diamonds from either raw unprocessed rock or tailings from a larger plant. The plant has been extensively modified to minimize potential mineral trap sites as well as to provide the ability to dismantle every portion of the plant that contacts the sample material and allow for meticulous cleaning between samples. The 150mm cyclone plant has a maximum rated throughput of 1.5 tonnes/hour of sample material using a lower cut-off of 0.8mm, but is also capable of recovery down to 0.3mm at a throughput of approximately 300 kg/hour. This lower threshold is very useful for diamond distribution curve information. The 100mm cyclone is useful for very large till or alluvial samples where either diamonds, kimberlite indicator minerals or any heavy mineral extraction is required from disaggregated material.
In order to ensure maximum diamond liberation a five stage crushing process has been added to the plant. A primary jaw crush can be set to meet the material requirements. Four additional crushing regimes may be utilized within the flow of the plant as required for optimal performance. Three cone crushers and one jaw crusher are used to gradually mill the material down in stages as material is passed through the separation process multiple times to extract the diamonds with minimal diamond breakage. The resultant concentrate is then subject to a caustic dissolution process to further liberate any diamonds still contained in, or attached to rock fragments. The concentrate is then observed for diamonds.
The plant is subject to ongoing quality control checks and procedures. Synthetic diamonds are added to the raw material to check the recovery of the entire process. All screens and crushers are tested to ensure proper operating parameters and the separation process is monitored using density tracer beads, allowing the operator to constantly monitor the effectiveness of the separation. This plant is highly adaptable to meet the needs of any client. Processes may be added or removed to suit the material and the clients needs.