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14 safety higher than 2.0 were obtained for a cut slope 2 (H) ' 1 (V); the cut slope has to be dewatered to the depth of 10 feet. The crest of the cut should be at a safe distance ' of at least 15 feet from the toe of the steep natural slope above the proposed entries. The underground drainage system installed to prevent the saturation of the entire cut height ' should be capable of dewatering a layer at least 10 feet thick; the cut slope should be dewatered for its entire ' height, i. e. between the cut toe and the crest. ' S. The same solution as recommended for entry 3 (elim- inating the retaining wall and replacing it by a cut slope) ' ~ ~ can be applied for entries 2 and 4; the. same criteria as recommended above should be applied for these portals. ' 6. The analyses were performed and recommendations made ' for cut configurations as indicated on Plates 2 - 6; if the l d h t fi i f i id bl diff h na ese cu es gn o t s cons era y erent, t s e recommendations should be revised. 1 The dewatering recommended in this report can be achieved ' by various methods; two of them appear to be feasible for this purpose: horizontal (or slightly inclined) drains and/or ' vertical trenches filled with pervious material. ' Horizontal drains comprise an effective means of dewatering. They are horizontal or inclined holes drilled into the slope ' to be dewatered; slotted PVC casing is installed in the holes. ll Pl h h f h 13 own on A met drain insta ation is s ate ; t e od o system uses a specialized drilling rig named an Aardwark. A ' scheme of possible drain installation for the proposed mine ~ entries is shown on Plate 14. The drains are drilled in fans ' ~ from several locations; their length is such that they reach some 120 feet behind the retaining wall. The drains should be 1 on«roao mwwMO, nc