2011-01-19_REVISION - M1987049 (7)

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Mr. David Bird December 15, 2010 Page Three of Five In 2007 RMCC paid for the installation of two (2) 5,000 gallon water storage tanks at Petrocco's direction; During mining RMCC will monitor ground water elevations on a weekly basis and report the results to Petrocco and, If Petrocco Farms notifies RMCC that water is needed, the company will begin pumping water and if necessary, delivering water by truck to refill Petrocco's water storage tanks Finally, in the event that other owners of nearby alluvial wells indicate that mining has adversely impacted their wells RMCC will first take steps to provide neighbors with a reliable supply of potable water and second take steps necessary to mitigate ground water impacts due to mining. Since the installation of the water storage tanks Petrocco has drilled several deep aquifer wells. Existing alluvial wells are used in the greenhouses and to irrigate growing beds. The water storage tanks were installed to provide water to the greenhouses and function as backup to the shallow alluvial wells typically used for that purpose. In a follow-up Adequacy Review letter dated September 4, 2009 Division staff asked RMCC to address the following concerns about ground water mounding related to the proposed slurry wall for water storage west of Brighton Road: "The Division believes ground water mounding is a valid issue and a monitoring plan is necessary. Ready Mix has four ground water monitoring wells in place to monitor ground water elevations during the mining process. These wells need to continue to be monitored until final bond release or the permittee can demonstrate to the Division's satisfaction that the ground water regime east of the slurry wall has not been impacted by its installation. It appears the closest structure to the proposed slurry wall is located on the Spier property at the south east portion of the expansion area. There are no monitoring wells between the proposed slurry wall and the property, so it will be difficult to determine mounding impacts to this property. At least two monitoring wells should be installed near the Spier property between the slurry wall to determine base ground water elevations at this location and to measure the ground water impact after the site is reclaimed the slurry wall is installed Please submit a ground water monitoring plan. Include in the plan defined ground water elevation trigger points and a mitigation plan if these trigger points are met."