2006-02-02_GENERAL DOCUMENTS - M1999120

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DIVISION Z -SITE WORK SECTION 02168 -SLURRY WALL CONSTRUCTION PART1-GENERAL 1.01 SCOPE OF WORK These specifications have been prepared by Deere & Ault Consultants (Design Professional) for Compass Environmental (Contractor) and includes the requirements for the Slurry Trench Cutoff Wall and related work as indicated on the drawings and as hereinafter specified. The work consists of furnishing all plant, labor, equipment, materials, and performing all operations as required to construct the slurry trench cutoff wall as specified by the contract documents. 1.02 QUALIFICATIONS OF CONTRACTOR The Contractor shall submit evidence that he is experienced and competent to construct asoil-bentonite slurry trench. This evidence will ensure that the Contractor has sufficient, competent experienced personnel to carry out the operations specified. In particular, a slurry trench specialist (as approved by the Owner) shall supervise the construction, slurry preparation, and quality control. 1.03 SOIL-BENTONITE SLURRY WALL The soil-bentonite slurry wall will be constructed to the lines, grades, and cross-sections as indicated on the drawings and the specifications. The trench shall have essentially vertical walls, a minimum width of 2.5' wide, and will extend through the overburden and sand and gravel strata, and key a minimum depth of 4' into the underlying claystone bedrock. The intent of the slurry wall construction is to provide a low permeability cutoff wall around the project site as defined in the contract documents. This slurry wall shall be constructed to meet the design standard as set forth in the Colorado State Engineer's Office guidelines ("State Engineer Guidelines for Lining for Gravel Pits," August 1999) with respect to the allowable leakage rate through the slurry wall component of the reservoir lining system. Other liner components such as sealing the reservoir bottom or bedrock within the interior of the reservoir are not included in the scope of this work. PART 2 -MATERIALS 2.01 SLURRY Slurry shall consist of a stable colloidal suspension of bentonite in water and shall be controlled in accordance with the most current API Standard 13B, "Standard Procedure for Testing Drilling Fluids," and the following requirements: A. At the time of introduction of the slurry into the trench, the slurry shall be a mixture of not less than 16 pounds per barrel (42 gallons) of bentonite and water. Additional bentonite and/or soda ash may be required depending on the hardness and temperature of the water and the quality of the bentonite. The slurry shall have a minimum apparent viscosity of 15 centipoises or 40-seconds reading through a Marsh Funnel Viscosimeter, a maximum filtrate loss of 30 cubic centimeters in 30 minutes at 100 psi, and a pH of not less than 8. B. The slurry mixture in the trench will have a unit weight not less than 64 pcf (1.03 gm/cc), not greater than 87 pcf (1.40 gm/cc), or as approved by the Owner. C. The slurry mixed with backfill material shall be either slurry taken from the trench or slurry meeting the requirements of slurry introduced into the trench. 02/06 Section 02168 -Page 1 of 5