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lower the viscosity, and generally higher pumping pressures are needed than normally used with cement grout. Bentonite chips: These grout products, commonly known as "Hole Plug", or medium and coarse Enviroplug, are intended to be poured into the well to form a seal. The materials readily absorb water and form a very low permeability and permanent seal. Being denser than water they can be poured through standing water. Other materials for filling: In cases where no sealant is needed to prevent water flow and materials are only needed to fill the well, coarse sand or graver may be employed. These materials should be clean and not contaminated,and of a particle size which minimizes the potential for"bridging" during placement. SEALING OPERATIONS Casing Destruction Well`destruction operations performed prior to or simultaneously with the sealing of cased wells may involve pulling any existing casing out of the ground as applicable and/or feasible, or perforating or other means used to cause openings in the casing large enough fo the sealing material to 'pass into the borehole. Openings in the casing may be made with an air-percussion perforator, ripped with a mechanical knife or similar device, or destroyed using explosives. In some situations where it is not possible to remove the casing or the casing is too_deteriorated to use perforating tools, explosives are an acceptablealterative. Some of these situations include PVC casing,wells with liners, wells with physical restrictions (e.g., breaks, ovals, drop pipes,etc.)and wells with deteriorated casings. Placement The appropriate 'sealing materials are placed from the bottom of the well up,``using a tremie pipe which is kept submerged in the mixture and is periodically raised as the well bore is filled in one continuous operation. However, special situations may dictate two or more stages. Some applications may call for pressure grouting. In some deep wells where lost circulation of cement into the formation behind the casing might result(or actually occurs);from the fracture gradient of the formation being exceeded, use of additives that lighten the mixture, and emplacement in a minimum of two "stages" may be necessary. With any sealing method, the volume of the hole to be filled should be calculated,;and compared with the volume of sealing materials used,to be sure that the volume of materials emplaced is at least equal to the hole volume. Casing Destruction Using Explosives Blasting work in water wells requires a C-57 water well contractor license and the blaster must hold a current CAL-OSHA license for blasting water wells. The California State License Board (CSLB) licenses Drilling. Blasting, and Oil Field Work under specialty classifications C-61 contractors with D-09 classifications does not include water well work or drilling. The "Blaster in Charge" is in control at the blast site. He is responsible for the safety of the explosive products used, product placement, and blast design. Sealing material should always be placed in the well prior to initiating the casing destruction process with explosives. This routine prevents the possibility of casing pieces and other debris from flying out of the well creating a potentially dangerous situation white the subsequent caving and/or sloughing prevents proper placement of the sealing material. When the sealing materials are placed in the well, the blast simultaneously opens the casing and pushes (pressure grouts) the sealing material into the annulus and borehole. Oilfield practices utilizing gun and jet perforating use products that contaminate are not allowed in water wells. ARTICLE 299—DESTRUCTION OF WATER WELLS —Page 3 of 8(Revised 4/27/2013)