Abstract:

The article introduces some new research results on gold ore characteristics in Nam Kha A region by analyzing supplemented thin slices, rninerals,... combining the Processing of research documents of previous periods by some geological methods. The results of the study drăw some conclusions: The original goid ore bodies in the region of mainly clrcuits, lens circuits, small to medium size, discontinuous distribution. The depth of exisíing ore bodies relative to the current terrain surtace is quite large, ranging from 100150 m or more. The ore body thickness from 0.63 m to 10.32 m, average 1.11 m to 3.95 m, and the variation is unstabie. The mono-ore body is tilted to the northeast, with a major slope of 20° to 40°. The mineral composition is very complex, minerals include pyrite, chalcopyrite, au natal, gallenite, hematite, sphalerite, less common arsenopyríte, ilmenite. Minera! ores 'veathering include geothite, limonite, boronite, covelite, Copper ore itself. The Au content according to the analysis results in the ore body varies from 1 g/T to>47.1 g/T, average from 1.9 to 6.6 g/T, some places ineet the gold ore Very rich (over 100 g/T). The purity of native gold in the study region was quite high, ranging from 63.3 % to 90.52 %, mostly over 80 %. Golden ore bodies in the origin of the hydrothermal origin (?), in the style of quartz-sulfide-gold, distributed in the sediment of acid-alternating pulp, claystone is converted into quartz-sericite-pyrite shale, quartz-sericite-chlorite-in the subclass On the Nam Kha A formation (Cr2nk). This is the area with great potential of origìnal gold, it is necessary to continue to investigate and expand the south-vvest of zone II and the contiguous part betvveen zone I and zone II; In the next study, we shouỉd pay close attention to the ore bodies hidden deep.