Resource modelling of inhomogeneous mineral deposits has evolved over time, now using both enhanced computing power to develop spatial relationships as well as sampling systematics to collect more and bigger samples. Kimberlite-hosted diamond mines have made the collection of large sample sizes as a mechanism to deal with sparse and inhomogenously distributed minerals of interest common place. High-grade gold mines can also suffer from inhomogeneously distributed gold values, yet with rare instances, solutions historically focus on more small samples and more computer power rather than bulk samples.
A review of three past-producing Yellowknife gold mines is presented to illustrate the distribution of grades in Yellowknife gold deposits. The Discovery Mine 100 km north of Yellowknife produced 3,110 kg of gold from 910,000 tonnes of ore between 1949 and 1969 and is an example of the nuggety nature of gold quartz veins in the Yellowknife Gold Belt. The Con Mine south of the city of Yellowknife produced 186,000 kg of gold from 10,900,000 tonnes of ore between 1937 and 2006 and is an example of shear zone-hosted gold mineralization. Neither had an ore reserve when production started as it was recognized that bulk samples from these promising deposits was required prior to developing a resource. The Mon Gold Mine is located 45 km north of Yellowknife produced 460 kg of gold from 13,600 tonnes of ore between 1990 and 1997. It is currently under development by New Discovery Mines Ltd and Sixty North Gold Mines Ltd and has not got a published Mineral Reserve or Resource.