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DIVISION 2 - SITE WORK <br /> SECTION 02168-SLURRY WALL CONSTRUCTION <br /> PART 1-GENERAL <br /> 1.01 SCOPE OF WORK <br /> These specifications have been prepared by Deere&Ault Consultants(Engineer)for the Stonewall Springs <br /> Quarry Southwest Reservoir Slurry Wall and includes the requirements for the slurry trench cutoff wall and <br /> related work as indicated on the drawings and as hereinafter specified. The work consists of furnishing all <br /> plant,labor,equipment,materials,and performing all operations as required to construct the slurry trench <br /> cutoff wall as specified by the contract documents. <br /> 1.02 QUALIFICATIONS OF CONTRACTOR <br /> The Contractor shall submit evidence that they are experienced and competent to construct a soil-bentonite <br /> slurry trench. This evidence will be used to verify that the Contractor has sufficient,competent experienced <br /> personnel to carry out the operations specified. In particular,a slurry trench specialist(as approved by the <br /> Owner)shall supervise the construction,slurry preparation,and quality control. <br /> 1.03 SOIL-BENTONITE SLURRY WALL <br /> The soil-bentonite slurry wall will be constructed to the lines,grades,and cross-sections as indicated on the <br /> drawings and the specifications. The trench shall have essentially vertical walls,with a minimum width of 2.5 <br /> ft.It will extend down through the topsoil,overburden and sand and gravel strata,and be keyed to a minimum <br /> depth of 4' into the underlying suitable shale bedrock. The intent of the slurry wall construction is to provide a <br /> low permeability cutoff wall around the project site as defined in the contract documents. <br /> This slurry wall shall be constructed by utilizing the design criteria set forth by the Division of Reclamation <br /> Mining and Safety(DRMS)in its"Guide to Specification Preparation for Slurry Walls and Clay Liners as a <br /> Component of Colorado Mined Land Reclamation Permits,"September 2000 or equivalent design criteria so <br /> that the work will meet or exceed the Design Standard as set forth in the Colorado State Engineer's Office <br /> guidelines("State Engineer Guidelines for Lining for Gravel Pits,"August 1999)with respect to the allowable <br /> leakage rate through the slurry wall component of the reservoir lining system. Upon completion of <br /> construction,the slurry wall shall undergo a 90-Day Liner Leak Test to test the performance of the slurry wall <br /> against the State's Design Standard for leakage. Other liner components such as sealing the reservoir bottom <br /> or bedrock within the interior of the reservoir are not included in the scope of this work. The work will not be <br /> considered complete or accepted if it does not pass the aforementioned"90-Day Liner Leak Test". <br /> PART 2—MATERIALS <br /> 2.01 SLURRY <br /> Slurry shall consist of a stable colloidal suspension of bentonite in water and shall be controlled in accordance <br /> with the most current API Standard 13B,"Standard Procedure for Testing Drilling Fluids,"and the following <br /> requirements: <br /> A. At the time of introduction of the slurry into the trench,the slurry shall be a mixture of not less than <br /> 16 pounds of bentonite per barrel(42 gallons)of water. Additional bentonite and/or soda ash may be <br /> required depending on the hardness and temperature of the water and the quality of the bentonite. The <br /> slurry shall have a minimum apparent viscosity of 40-seconds reading through a Marsh Funnel <br /> Viscosimeter,a maximum filtrate loss of 30 cubic centimeters in 30 minutes at 100 psi,and a pH of <br /> not less than 7 and not greater than 10. <br /> B. The slurry mixture in the trench will have a unit weight not less than 64.3 pcf(1.03 gm/cc),not <br /> greater than 87.4 pcf(1.40 gm/cc),and shall have a unit weight at least 15.0 pcf less than the unit <br /> weight of the soil-bentonite backfill. <br /> February 2016 Section 02168-Page 1 of 6 <br />