S.J Yousefi; A Aftabi; A Moradian
Abstract
Gossan occurs considerably around the Chahar Gonbad copper-gold mine. The mineralogy of gossan includes: hematite (Fe2O3), goethite (FeO(OH)), and limonite (Fe2O3.H2O) with colloform texture, as wewll as quartz, calcite and clay minerals. Enrichment factors include: Ag=1.08, As=1.19, Bi=70.12, Mn=4.11, ...
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Gossan occurs considerably around the Chahar Gonbad copper-gold mine. The mineralogy of gossan includes: hematite (Fe2O3), goethite (FeO(OH)), and limonite (Fe2O3.H2O) with colloform texture, as wewll as quartz, calcite and clay minerals. Enrichment factors include: Ag=1.08, As=1.19, Bi=70.12, Mn=4.11, Mo=2.37, Pb=1.51, Sb=1.7 and Fe=1.71 in comparison to the mineralized rocks. However, Cu=0.03, S=0.03 and Se=0.04 are strongly depleted; Zn= 0.94 is slightly depleted. Based on correlation coefficients, four droups can be distinguished. The first group includes Bi, Cu and Sb which have a good correlation with Fe and Mn. The reason for this correlation is probably the adsorption of Bi, Cu and Sb by iron and manganese hydroxides - oxides in gossans. The second group comprises of Pb and Ag which have a good correlation with Bi, Cu, and Sb, without any relationship with Fe and Mn. The third group elements are As, Mo and Zn which have no correlation with Fe and Mn, as they form insoluble complexes. The fourth group includes sulfur and selenium which formed by sulfide weathering, gossan formation and sulfate minerals. The correlation of Bi with Cu is caused by weathering of sulfide minerals and formation of gossan. Bi, Cu and Au enrichments in the gossan are 3123.94, 12.62 and 400 times the clarck values. All the elements in the gossans, in particular Bi could be considered as the possible exploration guides around Chahar Gonbad area.
S.J Yousefi; A Aftabi
Abstract
The investigation on toxic elements in sediments around the Chahar Gonbad copper-gold mine indicates sediments with various sources of pollution. In order to investigate the source and chemical fractionation of toxic elements 38 sediment samples were collected from 0 to 5 cm depth of river, alluvium ...
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The investigation on toxic elements in sediments around the Chahar Gonbad copper-gold mine indicates sediments with various sources of pollution. In order to investigate the source and chemical fractionation of toxic elements 38 sediment samples were collected from 0 to 5 cm depth of river, alluvium and dam sediments randomly. The average values of elements in sediments are: 0.09 ppm Ag, 17.82 ppm As, 0.48 ppm Bi, 0.22 ppm Cd, 17.58 ppm Co, 91.49 ppm Cu, 43161.33 ppm Fe, 1152.83 ppm Mn, 0.97 ppm Mo, 41.5 ppm Ni, 10.82 ppm Pb, 484 ppm S, 1.3 ppm Sb, 0.13 ppm Se, 1.05 ppm Sn, 3067.67 ppm Ti, 0.35 ppm Tl, 126.5 ppm V and 90.82 ppm Zn, respectively. The average values for waste dam sediments include 0.22 ppm Ag, 28.37 ppm As, 13.14 ppm Bi, 0.26 ppm Cd, 51.88 ppm Co, 1981.4 ppm Cu, 81677.33 ppm Fe, 2165.13 ppm Mn, 72.86 ppm Mo, 80.67 ppm Ni, 191.38 ppm Pb, 5593.17 ppm S, 47.75 ppm Sb, 0.66 ppm Se, 1.77 ppm Sn, 2136.83 ppm Ti, 0.43 ppm Tl, 80.75 ppm V and 989.94 ppm Zn. The obtained results were evaluated by using of multivariation statistical method including correlation coefficient, principal component analysis (PCA), and cluster analysis (CA). By using a multivariation statistical method it becomes obvious that the sediments can be divided into four different categories. The first category of these sediments are derived from mining activity, which in the first component of the PCA analysis are related to Ag, As, Cd, Co, Cu, Fe, Mo, Pb, Sb, Se, Sn, Tl and Zn. The second category of sediments are not affected by mineralization and in the second component of PCA analysis are indicated by Al, Sc, Sr, V, Ta, Ti. The third category is of natural sediments, on which, rock source and mineralization had an influence, thus include the third component of PCA analysis and are indicated by Bi, Mn, and S. The forth category of sediments include toxic elements such as Cr and Ni that either are derived from weathering of sulfides or probably from ophiolitic rocks.
