HOISTING BAGS – Gold bearing material is collected underground and brought to surface according to existing shaft procedures. At the shaft head the material is crushed before being placed in bags. The bags are transported to the sampling area at New Consort and stored, until the material can be weighed.
WEIGHING AND HANDLING OF BAGGED MATERIAL – Accumulated bags on surface are to be weighed before being discharged onto the conveyor belt, while the following procedures are adhered to:
- The scale must have an up to date certificate of accuracy.
- Each bag is weighed in the presence of a security person and signed off by that security person at the end of the batch.
- A bag must be discharged onto the belt after being weighed. No bag is allowed to be stacked after it is weighed.
- The crushed material is then accumulated in the storage bin.
SAMPLING OF BAGGED MATERIAL –
Once the material has been weighed and crushed, it is ready to be sampled.
The following procedure is to be adhered to:
- Sampling is to be carried out where the feed belt from the storage bin discharges into the tip.
- A clearly visible mark is to be painted on the feed belt.
- Every time this mark passes over the drive pulley, a shovel is to be passed through the falling stream and the accumulated material is then passed through a riffler.
- This process is to be repeated ten times. If the accumulated material through the riffler is too much to fit in a sample bag. The material has to be riffled again to reduce the volume. The two final bins will then each be placed in a sample bag.
- The one bag will be submitted for assay and the other bag kept as a reference for a minimum of two weeks.
- The reference samples are stored in a lock-up room at the survey office and the samples to be assayed are taken to the metallurgical plant, together with a checklist, for collection the following morning for transport to the assay lab. The sampling supervisor must accompany the samples that are taken to the plant where it is handed over to security.
- The last sample in a batch could consist of less than ten scoops. This must be indicated on the sample control sheet to enable correct weight for average grade calculation.
- Every completed sample must either be locked away or kept under constant surveillance.
- A moisture content of 2.5% is assumed for final tonnage calculation.
PERFORMANCE LAB PROCEDURE
The sample will be assayed for gold (2 x 25 gram).
The following methodology will be used for each sample:
- The sample will be crushed to 3mm and split through a Jones Riffler into four samples.
- An A and B sample will be milled (Pulverized) and then assayed for gold grade.
- If there is a greater than 20% discrepancy between the values obtained for A and B, then a third assay will be done using the C sample.
- The rest of the sample material will be kept at Performance Lab for reference purposes for one week after the assay reporting date.
ACCOUNTING PROCEDURE –
The Chief Surveyor or Geologist will be responsible for gold allocation.
- The assay results will be made available to the geologist as soon as they are available.
- The average value of the A and B sample will be used for the grade calculation.
- If the average value (of sample A and B) exceeds 100/g/t, then the value is capped to 100g/t for that sample.
- The geologist and a representative of VTN mining will reconcile weekly to make sure that the accounting is done correctly and that both parties agree to the results.
At the end of each production month, the gold to be allocated will be adjusted by:
- The overall on mine Plant Recovery and the BIOX® recovery.
- A gold allocation certificate signed by the Geologist, Chief Surveyor and VTN will be submitted to the Manager Finance & Admin to calculate payment.
