Bulletin . PLANWORMNGS BEI°NG DEVELOPED ^ccaniz Quick$ilvcrjninc CAMBRIA,CALIF Mapped by C IV Coryell l^nCKSlLVER RESOURCES. 143 section was cut was obtained by the writer on the 250-foot level ( below No. 4 tunnel). There is an exposure of the same or anotherbody of similar rock on the road between the mine and the furnaces(see Photo 31). It has not been opened up sufficiently underground,nor did the writer have sutficient time for field study to ascertain ifthis diorite-gabbro has had any connection witli the mineralization ofthe orebodies. The immediate walls of
Bulletin . PLANWORMNGS BEI°NG DEVELOPED ^ccaniz Quick$ilvcrjninc CAMBRIA,CALIF Mapped by C IV Coryell l^nCKSlLVER RESOURCES. 143 section was cut was obtained by the writer on the 250-foot level ( below No. 4 tunnel). There is an exposure of the same or anotherbody of similar rock on the road between the mine and the furnaces(see Photo 31). It has not been opened up sufficiently underground,nor did the writer have sutficient time for field study to ascertain ifthis diorite-gabbro has had any connection witli the mineralization ofthe orebodies. The immediate walls of the orebodies are composed of harder sand-stones than the ore itself: that on the northerly side being gray, andthat on the southerly side being darker and more compact (barren mud-rock). The actual ore boundary is merely a slip, in the sandstone,and very difficult to follow. In the earlier-worked sand orebody, thenorth wall was well defined, being an alta of black clay slate, but it. Photo No. 31. Plant of Oceanic Mine, San Luis Obispo County. The light streak belowthe arrow is the line of the open cuts. ran out to a point at the west end as the sand rock ran out. The bestore was obtained next to this alta. At the westerly end of the prop-erty, these formations can be traced the canon of Santa RosaCreek, but no ore values have been found there. The methods of mining used are a caving system and that known assublevel slicing. As used at the Oceanic, two main or working levelswere driven 150 vertically apart along the strike of the orebody for300. These are well timbered. At vertical intervals of 25 betweenthe two main levels, sublevels are driven. ^Mining begins on the farend of the block, where a raise has been cut through. The angle ofdrilling is such that the ore can fall freely to the lower l(V(l. and at thesame time permit handling of the machines. Holes are drivenabove and below on a slice and the two rounds of shots break throughit. and so on t
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