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APPENDIX D <br />March 2000 -5- 993-2099.150 <br />3.1 Historic Mining Maps <br />Many mining plan maps were prepared over the years showing the development openings <br />that have been progressively excavated on different mining levels and accessed from <br />various shafts. The plan maps only show the excavations on the working levels and do not <br />show stoping activities that were undertaken above or between the levels. <br />In order to develop a database of the underground workings within the limits of Phase IV, <br />Golder reviewed the underground working drawings stored at the Cresson site, and copied <br />all of the relevant drawings to a common scale of 1 inch to 50 feet. More than 70 plan <br />maps were identified and copied. <br />The plan maps were overlaid on one another to compare the relative accuracy and to <br />determine the maximum extent of the indicated workings on each level. Once overlaid, the <br />• geometry of common areas shown on different drawings was noted to be very consistent. <br />Discrepancies between the position of excavations were generally less than 5 feet, with <br />some local extremes being up to 25 feet. Many of the drawings showed areas that <br />overlapped with other drawings. It was possible to use these overlaps to construct a single <br />composite mine-plan drawing of the entire workings in the area (Drawing Nos. 1 and 2). <br />This mine-plan drawing identified the major shaft locations, and these compared favorably <br />with the locations of the shafts on the surface survey plans mentioned later. <br />In the Phase III area, many of the historical plan maps indicated the elevation of the levels <br />being depicted. This was not always the case for the historical plans within the Phase IV <br />area. The relative sequence of the levels below surface (i.e. whether one level was higher <br />or lower than another level) could often not be estimated from the information provided, <br />and it was not possible to assign elevations (known or estimated) in a similar manner to <br />that presented for the Phase III level plans. This influenced the location of the exploratory <br />drilling that was undertaken to date (e.g., workings where the depth below surface was <br />i.-m3ownNAL REPdItramApm.Dw Golder Associates