1994-04-25_GENERAL DOCUMENTS - M1977378

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JOHN F.ABEL.JR. MINING ENGINEER 310 LOOKOUT VIEW COURT GOLDEN.CO 80401 303-279-4901 FAX 27"163 April 25, 1994 Mr. Larry Perino Sunnyside Gold Corp. P.O. Box 177 Silverton, CO 81433 Dear Larry: This is the letter report ycu requested co.cernirg my Friday April 22, 1994 inspection of preparations for filling the first (secondary) B-Level/Brenneman bulkhead. The first B-Level /Brenneman bulkhead has been constructed as designed. The bulkhead thickness between the form is 3 feet, the downstream tensile reinforcement consists of #10 bars on 12-inch centers (two-way) , the upstream temperature and shrinkage reinforcement is #6 bars on 12-inch centers, as detailed in my February 21, 1994 memo. The rib, roof and floor irregularities observed within the form appear to be greater than either of the previous F-Level Brenneman bulkheads. The profiles provided indicate this observation is correct: - - Prepax`ations for- the- planned filling-"of the form with-.2500 psi, 28 day Strength-concrete on April 28, 1994 were inspected. The principle'work required before filling the first B-Level Bulkhead involves setting up the mixing station. The bagged concrete and mix water is on site at the concrete mixing station. The bagged concrete was covered with plastic sheets in case the presently dry storage location starts to leak. The fill pipe was optimally positioned at the highest point in the roof within the form. The plastic drain pipe installed to prevent the initial water and neat cement that will be used to slick the slick line from entering the form before concrete begins to come out of the fill pipe is an excellent innovation. The fill hose and several hundred feet of the slick line were in position and connected. The mine crew was connecting the remaining approximately 500 feet of the slick line between the mixing station and the form. I inspected and approve the work performed in grinding the weld beads that have been protruding inside the flanges of the slick line. The ribside drillholes for multiple temporary rebar pipe cleaning stands is a clever utilization of available conditions. The 22 degree slick line elbows should facilitate pumping at the bends in the B-Level drift. I also -approve eliminating.the right angle elbows-immediately outside the concrete pump. - I certainly can't think of what other measures can be taken to further reduce resistance in the 840-foot slick line.-