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Battle Mountain Resources—San Luis SL-SOP-Groundwater Well Decommissioning <br /> STANDARD OPERATING PROCEDURES i REVISION: 0-May 6, 2019 <br /> 6. Can the riser be pulled and is removal of the well desired? <br /> 7. Is the well a bedrock well? <br /> 8. If the monitoring well is a bedrock well, does it have an open hole? <br /> 9. Is there a well assembly (riser and screen) installed within the bedrock hole? <br /> Subsurface Conditions <br /> 1. Is the soil contaminated? <br /> 2. Does the well penetrate a confining layer? <br /> 3. If the well penetrates a confining layer, might over-drilling or pulling the <br /> casing cause contamination to travel up or down through a break in the <br /> confining layer? <br /> 4. Does the screened interval cross multiple water-bearing zones? <br /> For additional collection and verification of information, the "Monitoring Well Field <br /> Inspection Log" (Attachment 13-1) can be used during a field inspection. After the well <br /> has been located and the information gathered, one is ready to select the <br /> decommissioning procedure in accordance with Section 4. <br /> Special conditions, such as access problems, well extensions through capped and <br /> covered landfills and seasonal weather patterns affecting construction, should be <br /> assessed in the planning stage. Decommissioning work requiring the use of heavy <br /> vehicular equipment on landfill caps should be scheduled during dry weather (if <br /> possible) so as to minimize damage to the cover. If work must be performed during the <br /> spring, winter or inclement weather, special measures to reduce ruts should be <br /> employed to maintain the integrity of a completed landfill cover system. As an example, <br /> placement of plywood under vehicular equipment can eliminate deep ruts that would <br /> require repair. <br /> 4. DECOMMISSIONING METHODS <br /> The primary rationale for well decommissioning is to remove any potential groundwater <br /> pathway. A secondary rationale, often important to the property owner or owner of the <br /> well, is to physically remove the well. Removed well materials may be recycled and will <br /> not interfere with future construction excavation. Physical removal of the well by pulling <br /> is preferable to leaving casing in the ground. Due to the added effort, expense and risk <br /> involved with pulling, the decision of whether to pull or not should be a separate <br /> consideration aside from selecting the sealing procedure. <br /> One should select a decommissioning procedure that takes into account the geologic <br /> and hydrogeologic conditions at the well site; the presence or absence of contamination <br /> in the groundwater; and original well construction details. The selection process for well <br /> decommissioning procedures is provided by the flow chart, Attachment 13-2. Answers <br /> to the question in the preceding section are the input for this flow chart. The four primary <br /> well decommissioning methods are: <br /> 1. Grouting in-place; <br /> 2. Perforating the casing followed by grouting in-place; <br /> 3. Grouting in-place followed by pulling the casing; <br /> 4. Over-drilling and grouting with or without a temporary casing. <br /> SL-SOP Well Decommissioning <br /> Battle Mountain Resources, Inc. Page 5 of 21 M;M1 <br />