An Approach To Decrease Error And Increase Data Reliability In Drill Sampling For Gold

Even in an otherwise care-fully done sampling procedure, reducing subsample weight, or splitting, when the grain size of material is too large commonly generates significant error. Such error can be estimated from the standard deviation of differences between values of PAIRED ASSAYS. Samples from split-ting steps immediately before comminution, and showing a restricted range of grade, generate paired assays. Splitting steps characterized by relative standard deviations exceeding 16% generate nonrepresentative data. Such steps should be redesigned to optimize reliability of assay-dependent studies. A sampling scheme can be graphically characterized, and then redesigned as appropriate, using a SAMPLING NOMOGRAPH. Use of the nomograph avoids continued replication of assays. Generally at a splitting step, excessive error can be reduced by comminuting more material. Unnecessary effort can be mitigated by comminuting less finely and/or by splitting to a smaller weight.