Reducing grade uncertainty in high-nugget effect gold veins-application of geological and geochemical proxies
Dominy, S.C., and Johansen, G.F. (2004) Reducing grade uncertainty in high-nugget effect gold veins-application of geological and geochemical proxies. In: Papers from PACRIM 2004 Congress, pp. 291-302. From: PACRIM 2004 Congress, 19-22 September 2004, Adelaide, SA, Australia.
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The erratic and localised occurrence of economic gold grades is a common feature of high-nugget effect gold veins. The nugget effect is a consequence of small-scale geologically controlled enrichment, and the inclusion or exclusion of sparse gold particles because of the sampling process. Such deposits do not always contain visible or coarse gold, and can be characterised by fine gold particles. Economic grade accumulations are generally contained within discrete oreshoots, which are surrounded by barren to low-grade material. Problems are often encountered where small sample types (eg drill core or channel samples) often vastly understate in situ grade, due to their general inability to intersect rare gold particles. As a result, the definition of grade and its distribution is often challenging, and leads to substantial resource uncertainty. Proxies, or indicators for grade, can help the geologist gain a better understanding of grade distribution and grade potential. These are based upon geological (eg mineralogical, textural, etc) and/or geochemical (eg specific elemental ratios, fluid inclusion compositions, elemental correlations, etc) criteria. The paper discusses the use and application of such proxies through three case studies.
|Item Type:||Conference Item (Refereed Research Paper - E1)|
|Date Deposited:||12 Nov 2010 04:30|
|FoR Codes:||04 EARTH SCIENCES > 0403 Geology > 040307 Ore Deposit Petrology @ 100%|
|SEO Codes:||84 MINERAL RESOURCES (excl. Energy Resources) > 8401 Mineral Exploration > 840105 Precious (Noble) Metal Ore Exploration @ 100%|