Laserfiche WebLink
<br /> <br /> 2.0 PROPOSED HYDRAULIC BARRIER ALIGNMENT <br />' The location of the proposed slurry wall between the West Pit of the mine and the Rito Seco <br /> is shown on Figure 1. The proposed alignment is approximately west to east. Figure 2 is an <br /> west-east geologic cross-section constructed from available monitoring well geologic sample <br /> descriptions using information for wells located near to the proposed slurry crap alignment. <br />' Well logs used in the generation of the geologic cross-section aze presented in TR-26. The <br /> total length of the proposed hydraulic barrier is approximately 1670 lineal feet. <br />1 <br /> 2.1 Geology <br /> Th <br />h <br />l <br />i <br />f <br />i <br />f i <br />L <br />i <br /> ere aze t <br />ree geo <br />c <br />og <br />ormat <br />ons o <br />nterest at the San <br />u <br />s Project: (1) Precambrian age <br />' bedrock, (2) Tertiary age Santa Fe Formation, and (3) Quaternary age Rito ~ eco alluvium. <br /> The objective of the slurry wall is to place the slurry wall in the alluvium ani key into the <br />' Santa Fe Formation or the Precambrian bedrock. <br />' 2.2 Precambrian Bedrock <br /> The Precambrian bedrock at the San Luis Mine site is composed of t~iotite gneiss, <br /> hornblende-biotite gneiss, pink gneiss, and igneous intrusions. Much of the bi~~tite gneiss in <br /> the mine azea has been hydrothermally altered, with a brecciated matrix replaced by an <br />' assemblage of silica, fine-grained muscovite, and pyrite. A large portion o~' the exposed <br /> West Pit wall is composed of silicified Precambrian biotite gneiss. <br />' k i <br />d W <br />Pi <br />ll <br />h <br />P <br />i <br />d <br />Al <br />h <br />li <br />f <br />h <br />l <br />b <br />b <br /> s <br />e propose <br />t s <br />urry wa <br />, t <br />e <br />recam <br />r <br />an <br />e <br />roc <br />ong t <br />e a <br />gnment o <br />t <br />est <br />' expected to be primarily un-weathered biotite gneiss. Monitoring wells M-l6 and M-30 <br />30 <br /> encountered Precambrian rock as shown on Figure 2. The geologic log for well M- <br />' indicates that the boring penetrated 52 feet of alluvial material before encountering <br />approximately 23 feet of "blue" clay. This "blue" clay is interpreted on Figure 2 as possible <br />' Precambrian fault gouge material of the unit locally termed the "Green Clay". 'T'his clay fault <br />gouge zone is associated with the gold deposit at the San Luis Mine. Well M-l6 penetrated <br />54 feet of alluvial material before penetrating Precambrian gneiss; no "Green Clay" was <br />encountered. <br />' Bat!!e Mountain Resources, lnc. Shepherd Miller, lnc. <br />' v: voase; ~sn,,.ywum~r,;~po.~.,e.~ 2 November 5, 1999 <br />