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PHILLIPS MINING, GEOTECHNICAL 8 GROUTING, INC. <br />Grouting will be performed through 2 inch standpipes that were previously cast into the <br />concrete and are fitted with suitable valves. Because of the timber cribbing in the back of <br />the drift and the timber sets, it will be necessary to pre-place these standpipes. In this way <br />it can be ensured that later drilling does not have to contend with the problems of drilling <br />through a composite of concrete and thick timber sections in order to install the standpipe <br />and/or extend the grout hole. <br />It is anticipated that approximately 2 rings of 8 grout holes will be required in each plug <br />section to adequately perform the grouting. The grouting sequence will utilize primary <br />and secondary sequencing of the holes and will be performed in stages in each hole. The <br />depth to which these holes are drilled and grouted will depend upon the actual site <br />conditions encountered, but the drilling equipment must be available and capable of <br />drilling 1 e to 1 e inch diameter holes to a minimum of 20 feet, at an acceptable rate of <br />penetration. <br />Grouting of the concrete/rock interface and of the rock itself, will be performed with acid- <br />resistant cements, either one that has a particle size distribution similar to Type UII <br />cement, such as Fosroc Terracem, or an ultrafine cement, such as Fosroc Ultracem. The <br />choice between the two types of cement will be determined by the size of the <br />frachue/opening to be grouted, as determined by water injection testing. Both grouts are <br />recommended as they are very resistant to acid attack. Grout pressures up to 40 psi will <br />be used for the grouting procedures. At the completion of gouting, all the holes will be <br />filled and plugged with a thick cement mix (a water cement ratio of at least 0.7;1 by <br />weight). <br />The grouting equipment will consist of a high shear colloidal mixer, such as a concrete <br />mixer or equivalent, a paddle type holding tank and a progressive cavity grout pump, such <br />as a Moyno pump or equivalent. The pump must be capable of pumping cement grouts <br />Page 9 <br />