Resource Estimation - Sampling & Analysis
The collection of reliable samples from a mineral prospect or mine is an essential basis for the production of an accurate resource estimate. The strategy to be adopted must thus be carefully designed so that at each stage of the process, the chance of taking biased, unrepresentative or contaminated samples is minimised.
Sampling and sample preparation protocols should be designed to produce the highest possible data quality given the nature of the target mineralisation and the ground conditions. Issues addressed in such protocols include the following:
- Optimum sample length, volume or weight and compositing strategy in relation to the physical characteristics of the mineralisation
- Optimum sampling methodology and collection procedure to minimise contamination, avoid loss of fines in the case of rotary percussion drilling, and to produce representative unbiased samples
- The establishment of on-site supervision and checking procedures for drilling and sampling programmes
- Monitoring of sample recovery
- Sample homogenisation and splitting procedures
- Duplicate sampling at each stage in the reduction and splitting process to determine the magnitude of errors at each stage
- Quality control procedures to monitor sample preparation and analysis at the mine or commercial laboratory
- Replicate sampling and analysis to determine precision of sample grades
- Comparative studies between assay laboratories and determination of accuracy
- Compatibility of assay databases produced by different sampling campaigns
SRK has the capability to assess a client's existing sampling programmes in order to determine whether the strategy employed by the client is meeting set aims and objectives. SRK considers key factors in executing these evaluations, such as, whether the correct sample volume is being taken, whether a change could be introduced which would have significant impact and be cost effective and whether the drillhole or sample layout will provide the level of confidence sought for the subsequent resource estimate.
SRK has the expertise to design, manage and audit sample collection and preparation procedures on behalf of clients in both the mineral exploration and mining industries. This expertise has been developed over 25 years during the supervision and auditing of drilling programmes undertaken as part of exploration projects and mine feasibility studies and also during the performance monitoring of operating mines. In addition, sampling programmes have been designed for base line environmental geochemical studies and for the assessment of contaminated mine sites.
SRK technical staff have the necessary statistical/geostatistical expertise and computer software to undertake in depth studies of the assay information obtained from sampling campaigns and to produce detailed conclusions and recommendations.