Indicator Mineral Processing

Indicator mineral processing is generally used on sediment samples deposited by glaciers (till) or water (stream sediment). Diamond indicator minerals found in kimberlite are known to have formed at the same temperature and pressure as diamond but are much more abundant. As a result of this it is easier to find these minerals in proximal sediments and trace them back to their source, where we hope, we will also find diamonds.

Heavy, dense liquids are used to separate these indicators from the rest of the sediment. The indicator minerals, like pyrope garnet, are more dense than the surrounding liquid and sediment and sink to the bottom leaving the remaining material floating.

The concentrate created by this process is then sent to microscope observation to be picked, identified and analyzed.

Laboratory Information

Microlithics Laboratories utilizes several QA/QC measures during the processing of IM samples through the lab. A quality control grain spike process involving a dual stage grain insertion into the sample is done on up to 10% of the samples. Before the sample is started through the processing system (but after the ICP sample is taken if requested) a set of Blue Corundum grains are inserted into the sample. Once the dry sieving stage is complete but prior to the first stage of liquids another set of Synthetic diamond grains are inserted in the portion of the sample destined for liquid separation. Photographs of the grains and their insertion are recorded. After the sample has passed entirely through the lab and depending on the clients request Microlithics can do the observation to remove the grains and provide the results of the tests. Otherwise the sample is passed along to the observation lab who can report back to the client the results.

QA measures are in place to assure sample quality. Prior to the start of a sample a numbered ceramic ball is placed within the sample and will follow along within the processing material until the sample is complete through the sieving stages of processing. This allows an extra level of assurance that each sample started is the same sample upon completion. At each and every process, start and finish times are recorded to the minute. The station used for processing is also recorded as is the operator who started and who finished the sample at each station. The data that is collected from every sample is provided to the client upon completion of the sample. Barcodes are used to identify the sample in the LIMS to reduce user input error. Upon project completion or any time an invoice is prepared, data is provided in an excel spreadsheet and a custom client database which includes all photographs and station information.