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T ~ • <br />(Page 2) <br />MINE ID p OR PROSPECTING ID p M-86-104 <br />INSPECTION DATE :-26-99 INSPECTOR'S INITIALS ACS <br />OBSERVATIONS <br />On Alovember 12, 1996, B & B Excavating notified the Division of Minerals and Geology (DMG) <br />that two or three 56-gallon drums of herbicide had been emptied onto a crushed gravel <br />stockpile at the Montgomery Pit. On November 16, 1996, the DMG inspected the pIt to gather <br />information on this incident, and to work with B & B to develop a corrective action plan to <br />assess and mitigate any poten r.ial adverse environmental impacts. As a result, a sampling and <br />analysis plan was developed for a complete characterization of the effects of the herbicide <br />release. This March 26, 1999 inspection was conducted to observe the implementation of the <br />approved sampling plan. <br />Greg Lewicki, consultant to B & B was on-site to supervise the sampling. The sampling was <br />conducted by TechLink Environmental, Inc., represented by Carlos Tamayo and Dan Warner. Greg <br />Lewicki and Associates will be providing a complete report on the sampling and the analytical <br />results to the DMG, so only a brief summary of certain observations is made in this report. <br />The following water samples were collected: Surface water from the left bank of the Eagle <br />River upgradient and downgradient of the herbicide release site, ground water from a point <br />between the herbicide release site and the Eagle River. Seven soil samples from the <br />potentially contaminated 'h inch road base pile, 3 soil samples from the ground underlying the <br />former '/. inch minus crushed gravel pile where the release occurred, and one background or <br />"blank" soil sample. In addition, numerous ambient temperature headspace tests were <br />conducted on the K inch road base using a photo-ionization detector (PID). This was done <br />because the herbicide was carried in a petroleum distillate base. The PID readings indicated <br />that there is a very low concentration of volatile organics in the pile. <br />The ground water sample was collected by digging a backhoe (CAT 236C) pit in [he undisturbed <br />ground between the pit and the river. Ground water was encountered at about 6 feet, and the <br />water was allowed to settle for approximately 1.5 hours. The backhoe bucket had been steam <br />cleaned prior to digging the pit. The sample was collected using a new disposable bailer. <br />The PID samples were collected from numerous locations and at varying depths in the 'h inch <br />road base pile using a hand auger. Based on the PID readings, 7 locations in the pile were <br />identified for collection of lab samples. The lab sample locations included the areas with <br />the highest PID readings, and a variety of deep and shallow locations over the entire extent <br />of the pile. The lab samples were collected using a stainless steel hand auger that was <br />decontaminated between samples. The decontamination procedure occurred on a plastic tarp and <br />consisted of scrubbing with soapy water and rinsing with clean water. The same two 5-gallon <br />buckets of soapy and clean water were used throughout the process. <br />The soil samples from the ground beneath the site of the ?~. inch crushed gravel pile where the <br />release originally occurred were collected from three locations. The pile where the <br />herbicide was released has all been screened into X inch road base and ii inch rocc, so is no <br />longer present at the original release site. However, other clean gravel has been stockpiled <br />at the location. B & B personnel used a backhoe to clear the areas selected for subsoil <br />sampling and excavated three sample collection pits. It was observed that a dense layer of <br />silty sand was present in all three sampling pits. This dense, fine-grained layer would have <br />presented a low-permeability barrier to the migration of herbicide into the ground and to the <br />ground water. The subsoil samples were collected from between 1 and 3 feet beioca original <br />ground surface using a spade chat was decontaminated between each sample. <br />The background soil sample was collected from unmined ground at the east end of the permit <br />area in a location that could not have been effected by the herbicide release. The sample was <br />collected from approximately one foot depth in a preexisting pit using a decontaminated <br />