Prospecting Prediction Research For Geo-electric Extraction Method In The Permafrost Region

In recent years, the Qinghai-Tibet Plateau, which is characterized by permafrost landscape, become a new hot spot research area of Geological prospecting breakthrough in China. However, it is very difficult to carry out the conventional exploration methods in such a special landscape conditions. As a new prospecting method, the geo-electric extraction technique has its own advantages, and has been applied in various landscape conditions of elsewhere in China with good results. Nevertheless, it is uncertain whether this technique can be performed in the permafrost region.In this thesis, we take the Gadaban Copper polymetallic mine in Qilian County of Qinghai Province as an example. We carried out technical conditions comparison and feasibility study of the Geo-electric extraction method, in order to discuss the rationality of different technical parameters in the permafrost region. Consequently, the best parameters will be chose based on the analyzed characteristics and the similarities and differences of the geo-electric extraction anormaly. After that, the feasibility research and prospecting prediction works has been done in two other deposits(Duocaima and Zajiatongna) under the same landscape conditions. The modern statistical methods has been used to assess the characteristics of the geo-electric extraction anormaly, the abnormal range of single element was selected, the abnormal of elements was combined with the methods of factor analysis and cluster analysis.Progresses achieved in this study are summarized as follows:(1) By contrast of five different parameters, including voltage of power, concentration of extracting reagent, dosage, power time, and the distance between two electrodes, we finally figured out that the best parameters for prospecting in the permafrost region should be the following conditions: voltage of power is 9-12 V, extracting reagent is 1000 ml nitric acid with a concentration of 15%, power supply for 24-48 hours, the distance between two electrodes is 1m.(2) Eleven elements had been extracted from the Gadaban ore deposit, as a result, Ti and Ni showed the strongest anomaly, followed by Cu, Zn, Bi, and Pb, and the others has no anomaly.(3) In the feasibility study of three ore deposits, we noted that all the main mineral elements yielded obviously anomaly. In the Gadaban cooper-polymetallic ore deposit, the anomaly of Ti, Ni, Cu, Zn, Bi is obviously. In the Duocaima lead-zinc ore deposit, the anomaly of Cd, Pb, Zn, Au is obviously. In the Zajiatongna gold deposit, all elements of Au, Ag, As, Sb have obvious anomaly.(4) The element combination of forecast area is similar to the known section, and all have obvious concentration zoning. In the Gadaban forecast area there are two concentration centers, which have more obvious anomalies of Ti, Ni, Cu, and Zn, and the ore-control fault F39 is through nearby. In Duocaima forecast area, there is a large-scale concentration center, which have anomalies of Pb, Zn, Cd, Ag, Au, and Cu. The anomaly range covered the location of 3 known ore bodies and their eastern stretch, and three EW ore-control faults pass through. In Zajiatongna forecast area, other element has no repeatability with Au about anomaly, and there is no obvious concentration center.(5) Apparently, the geo-electric extraction method is very effective in the two poly-metalic deposits in the permafrost region, and the anomaly of ore-forming elements is obvious. In Gadaban deposit area, the anomaly of Cu and Zn is obviously, while Pb is not. In Duocaima deposit area, the anomaly of Pb and Zn is obviously, while Cu is not. Pb contents is closer to the soil. Meanwhile Ti, Ni, Bi anomalies are good in Gadaban deposit area, but whether good in other deposits is still uncertain.(6) In the permafrost region, the geo-electric method mainly extract Au anomaly of gold deposits, and the other elements do not show good correlation with Au.(7) We proposed a factorial analysis and contour line of element combined method. From the macro, using factor score shows good effective to control the selection of single element abnormally and combine elements abnormities. To a certain extent, the method invalid void(scattered) abnormaly.