Laserfiche WebLink
Appendix B - Packer Test Methods and Results 10 <br />• 5. PACKER TEST RESULTS <br />A total of 30 packer test were performed in seven underground boreholes at the Schwartzwalder Mine. The <br />packer tests were performed by Cotter personnel during the spring of 1999 according to methodology <br />prepared by Adrian Brown Consultants. The boreholes were located in the deeper levels of the mine (19 <br />level and 15 level) and selected to intercept native rock distant from the mine workings. The test holes, <br />diameters, and intervals are listed Table 1. <br />Most packer tests were straddle packers in existing coreholes. Single packer tests were conducted in <br />corehole 1910A, which was drilled for the purpose of packer testing the pegmatite zone in August 1999. <br />The field data sheets are provided in Attachment 1. <br />Of the 30 test conducted, 22 yielded analyzable data to determine the hydraulic conductivity (permeability) <br />of the deep underground bedrock. The analyses are provided in Attachment 1. Packer test results are <br />summarized in Table 2. <br />Hydraulic conductivity values calculated from the packer tests ranged from 3.3 x 10-5 cm/sec to 9.9 x 10-8 <br />cm/sec. The geometric mean hydraulic conductivity for all packer tests was calculated to be 4.7 x 10-7 <br />cm/sec. The median hydraulic conductivity was calculated to be 2.7 x 10 -7 cm/sec. Packer test results did <br />not indicate significant variation in hydraulic conductivity between the major lithologic units (LSHG, <br />GBG, and MS). In general, the permeability of unfractured bedrock was low (near 1 x 10-7 cm/sec). Four <br />of 22 tests returned values in the 10-6 cm/sec range and 2 of the tests indicated permeabilities in the low 10-5 <br />cm/sec range. Packer tests with hydraulic conductivities greater than 1 x 10-6 cm/sec are interpreted to <br />result from fracture flow, with permeabilities in the low 10-5 cm/sec range best representing the hydraulic <br />conductivity of transmissive fracture zones. <br />• Packer tests completed in intrusive pegmatite rocks also indicated low permeability (<1x10-7 cm/sec). In <br />contrast, the hydraulic conductivity of transmissive fracture zones is estimated to be on the order of 10-5 <br />cm/sec. This range is consistent with published values for fractured metamorphic rocks (Freeze and Cherry <br />1979) and professional experience at other underground mines in metamorphic terrains (Crandon Project, <br />Wisconsin; Monarch Mine, Venezuela; Midwest Project, Saskatchewan). These transmissive zones (faults, <br />fractures and pegmatites) are of limited distribution and extent but provided the bulk of the flow to the <br />underground workings during mine development and dewatering. The fact that the packer testing of <br />pegmatite zones resulted in a very low permeability (<1x10-7 cm/sec) probably reflects the small number <br />and limited aerial distribution of the packer tests rather than the actual range of permeabilities associated <br />with the pegmatites. <br />C <br />4109B.071116 Whetstone Associates