Laserfiche WebLink
Battle Mountain Resources—San Luis SL-SOP-Groundwater Well Decommissioning <br /> STANDARD OPERATING PROCEDURES REVISION: 0 -May 6, 2019 <br /> enough to penetrate the slots and sand pack. The grout mixes are discussed in <br /> Sections 8.1 and 8.2. <br /> 4.2. Casing Perforating/Grouting In-Place <br /> Casing perforation followed by grouting in-place is the preferred method to use if there <br /> is poor documentation of the grouting of the well annulus, or the annulus was allowed <br /> to be back-filled with cuttings. The grout will squeeze through the perforations to seal <br /> any porous zones along the outside of the casing. The procedure involves puncturing, <br /> cutting or splitting the well casing and screen followed by grouting the well. A variety <br /> of commercial equipment is available for perforating casings and screens in wells with <br /> four-inch or larger inside diameters. Due to the diversity of applications, experienced <br /> contractors must recommend a specific technique based on site-specific conditions. <br /> A minimum of four rows of perforations several inches long around the circumference <br /> of the pipe and a minimum of five perforations per linear foot of casing or screen is <br /> recommended (American Society for Testing and Materials, Standard D-5299). After <br /> the perforating is complete, the borehole must be grouted according to the <br /> procedures in Section 8 and the upper five feet of borehole restored according to the <br /> procedures in Section 9. <br /> 4.3. Casing Pulling <br /> Casing pulling should be used in cases where the materials of the well assembly are <br /> to be recycled, or the well assembly must be removed to clear the site for future <br /> excavation or re- development. Casing pulling is an acceptable method to use when <br /> no contamination is present; contamination is present but the well does not penetrate <br /> a confining layer; and when both contamination and a confining layer are present but <br /> the contamination cannot cross the confining layer. Additionally, the well construction <br /> materials and well depth must be such that pulling will not break the riser. When <br /> contamination is likely to cross the confining layer during pulling, a temporary casing <br /> can be used. See Section 4.4. <br /> Casing pulling involves removing the well casing by lifting. Grout is to be added during <br /> pulling; the grout will fill the space once occupied by the material being withdrawn. An <br /> acceptable procedure to remove casing involves puncturing the bottom of the well or <br /> using a casing cutter to cut away the screen, grouting, using jacks to free casing from <br /> the hole, and lifting the casing out by using a drill rig, backhoe, crane, or other suitable <br /> equipment. Additional grout must be added to the casing as it is withdrawn. Grout <br /> mixing and placement procedures are provided in Section 8. In wells or well points in <br /> which the bottom cannot be punctured, the casing or screened interval will be <br /> perforated or cut away prior to being filled with grout. This procedure should be <br /> followed for wells installed in collapsible formations or for highly contaminated wells. <br /> At sites in which well casings have been grouted into the top of bedrock, the <br /> casing pulling procedure should not be attempted unless the casing can be first <br /> cut or freed from the rock. <br /> SL-SOP Well Decommissioning EA, Inc. <br /> Battle Mountain Resources, Inc. Page 7 of 21 May 6, 2019 <br />