The fact that the pyrite is much more abundant in the ore bodies than in the wall rocks also suggests that the pyrite has various origins, because a simple sedimentary origin may not have provided all the pyrite cores that now exist.
Therefore, comparing the REE patterns in the ores and wall rocks may provide information on the nature of the ore-forming fluids.
The ores and wall rocks in the Bojitian deposit show similar REE patterns (Figures 8(a) and 8(b)), and both are richer in the LREEs than the HREEs, implying that the fluids that influenced the ores and wall rocks changed little over time.
The fractal model could be applied for defining sulfidic mineralized zones, especially high accumulation of sulfide minerals from the wall rocks, or from the background, based on data obtained from IP/RS exploration.
Table 1: Threshold values obtained by using N-S model based on Chargeability (mV/V) in Shadan deposit Zone Threshold Range (mV/V) (mV/V) Wall rocks -- 0-4.5 Low sulfidic zone 4.5 4.5-45 Moderate sulfidic zone 45 45-89 High sulfidic zone 89 >89 Table 2: Threshold values obtained by using N-S model based on resistivity (Ohm.m) in Shadan deposit Zone Threshold Range (Ohm.m) (Ohm.m) Wall rocks 891 >891 Low sulfidic zone 501 501-891 Moderate sulfidic zone 56 56-501 High sulfidic zone -- <56
Early-stage white muscovite and fluorite (commonly looks orange on mine walls, but is actually light green when removed and cleaned) contain pyrite; these minerals grade from wall rock replacement into open-space filling along vein walls.
This alteration replaces, to a greater or lesser degree, feldspars and biotite in the wall rock with sericite, some of it quite coarse-grained.
Three samples of sericite-altered wall rock, each adjacent to veins, were selected from different sites in the Sweet Home mine.
Furthermore, the shot lines greatly enhanced depressurisation of the wall rocks
, as shown by the hydrographs displayed in Figure 5.
In this method, wall rock has to be cut to make operation space.
In resuing, not only ore is mined out, but wall rock is cut as well to make a minimum working space (about 0.9 m).
No evaluation of possible larger scale open pit mining of lower grade material including the high grade shoots, their lower grade portions, stockworks of small veinlets, and intervening low grade, but extensively altered wall rock