X hits on this document





83 / 124

to drying trays and placed in a drying oven at approximately 140o C until dry. The dry sample was removed, weighed and sized for observation and diamond selection. MSC sieved to +6 mm,

  • -

    6 +4 mm, -4 +2 mm, -2 +0.85 mm and -0.85 mm fractions. At this point MSC removed any +6

mm visible diamonds and placed these in a bag for reporting. All size fractions were weighed, and were bagged and labelled. The +6 mm fraction was ready for sorting, and the -0.85 mm fraction was retained but not sorted. If sufficient sample was present in the middle fractions, these were subject to magnetic separation using rare earth magnets in a permroll belt separator. MSC used an Eriez permroll, which was modified to provide an initial step of scalping of the most magnetic material. The permroll provided three products – a non-magnetic fraction (that contains the majority of the diamonds), a para-magnetic fraction (this was re-run a second time) and the magnetic fraction. The machines were regularly calibrated and cleaned. The magnetic and size fractions were all weighed, labelled, documented and delivered to the sorting lab.

The grease table concentrate sample, which was generally quite small, was scraped from the sample container for degreasing. At MSC the grease sample was melted in a drying oven, decanted, and placed in a screen into a commercial ultrasonic degreasing machine. The process resulted in a sufficiently clean concentrate for sorting. The resultant degreased product was then dried, weighed, labelled, documented and delivered to the sorting lab. As the product was generally quite small, it was not sieved or magnetically separated.

The samples were received and logged in the sorting room. Trained mineral observers sorted each fraction for diamond selection. The non-magnetic fractions of each size were picked under a binocular microscope and diamonds were removed for verification and later classification. Each of the non-magnetic fractions was then re-sorted by another observer for quality control. The para-magnetic fraction was similarly sorted, but not all received a QC second sort. Generally the magnetic fractions were not sorted, but some percentage was sorted for QC purposes. The majority of the diamonds were recovered from the first sort of the non-magnetic fractions. The grease concentrate was sorted, and re-sorted for QC, as a single fraction. However, there were often intermediate stages to separate rubbish material (plastic, metal, etc) from the concentrate grains.

All diamonds were verified, counted and weighed individually and were preliminarily described as requested by Shore. The diamonds were classified by size fractions using both square mesh Tyler sieves and round hole DTC sieves. For each sieve type, each size fraction was counted and weighed and reported.

Results Summary

As can be seen in Table 13.3, all natural diamond tracers placed in the samples were recovered by Shore’s bulk sample plant, and all from the x-ray concentrate. The synthetic tracers were mostly recovered, with the loss of three 2 mm and one 4 mm tracers. Three of the 2 mm tracers were recovered on grease. In the opinion of Howe, this shows acceptably good recovery efficiency.

P&E Mining Consultants Inc. NI 43-101 Technical Report No 159 Shore Gold Inc. - Star Diamond Project Resource Estimate Update

Page 68 of 109

Document info
Document views392
Page views392
Page last viewedWed Jan 18 08:56:02 UTC 2017