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GRAINSIZE OF MINE ROCK HYDRAULIC CONDUCTIVITY OF MINE ROCK <br /> Adrian Brown, May 25, 2005 Adrian Brown, November 9, 2016 <br /> INTRODUCTION METHOD <br /> A test of grainsize was performed on run of mine ore rock at the Cresson Mine in April 2001. Hydraulic conductivity can be estimated using a formula attributed to Hazen (1893) and expanded by him in 1911: <br /> The samples were run-of-mine ore dumped at the crusher primary feed (before crushing). <br /> The size fractions were determined with a laser scanning visual imaging system developed by Split Engineering. K=C(d,o)2 <br /> Overburden is shot and hauled the same as ore samples, so data is considered also representative of overburden. <br /> where: K= hydraulic conductivity (cm/s) <br /> EVALUATION d,o =grain-size diameter at which 10% by weight are finer and 90% are coarser (mm) <br /> The mined grainsize data plot in a relatively fine band, with the following parameters C = coefficient based on table below <br /> Size Fraction mm inch Description of granular material C <br /> 90% passing 350 13.8 Very fine sand, poorly sorter 0.4-0.8 <br /> 50% passing (ave) 100 3.9 Fine sand with appreciable fines 0.4-0.8 <br /> 10% passing 8 0.3 Medium sand, well sorted 0.8-1.2 <br /> Coarse sand, poorly sorted 0.8-1.2 <br /> FIGURE 1: GRAINSIZE DISTRIBUTION OF MINE ROCK SAMPLES lCoarse sand, well sorted, clean 1 1.2-1.5 <br /> Developed with sands where cl,o is U.1 to 3.0 mm <br /> 100 <br /> HYDRAULIC CONDUCTIVITY OF MINE ROCK <br /> Assuming that the Hazen Formula is applicable to coarse rock particles: <br /> 90 <br /> K=C(d,o)2 <br /> 80 where: C = 1.5 Table above <br /> d,o= 8 mm Figure 1 <br /> 70 Then: K= 96 cm/sec <br /> REFERENCES <br /> Hazen, Allen, 1893. Some Physical Properties of Sands and Gravels, Mass. State Board of Health, 24"' Ann.Rpt. <br /> 60 Hazen, Allen, 1911. Discussion of"Dams on Sand Foundations", by A.C. Koenig,Transactions, ASCE, 1911. <br /> CU <br /> m <br /> m <br /> c 50 <br /> U <br /> L <br /> ^� I <br /> LL <br /> 40 <br /> 30 <br /> 20 <br /> 10 <br /> 0 <br /> 10000 1000 100 10 1 <br /> Grainsize (mm) <br /> --in—Test 1 —*--Test 2 — Test 3 Average Scale: As shown CC&V Amendment 11 H dro eochemist <br /> ry <br /> Drawn: A.Brown PLATE 32 Rev.2 <br /> AdrianBrown Date: 2016-11-09 HYDRAULIC CONDUCTIVITY OF OVERBURDEN <br />