Sand & Gravel Mining BMPs

Sand & Gravel Mining BMPs

General

  • A sand and gravel pit shall be located in area that precludes pit capture.  Pit capture occurs when a natural buffer separating a pit from a Scenic River is breached by streambank erosion, channel migration or overflowing floodwaters.  Therefore, pits shall be located outside of a Scenic River channel migration zone (i.e., area within which a river channel is likely to move over a period of time) and in areas not susceptible to inundation from overbank flooding.  Always contact the Scenic Rivers program before determining the location of the mining site.
  • Maintain vegetated buffers, a minimum of 100 feet in width, between land disturbance activities (e.g., construction of access and haul roads, wash plants, processing plants, maintenance and staging areas) and all intermittent and perennial streams that flow into Scenic Rivers.
  • Handle and store toxic and hazardous material such as fuels and lubricants outside of riparian areas.
  • Do not operate bulldozers, trackhoes, graders or other land-clearing equipment within wetlands or any perennial streams. 

Pre-Mining Phase

  • When constructing elevated access roads, install adequately sized culverts to carry surface water flow across the road.  Culverts should be maintained to ensure that existing flow of surface water is uncompromised.
  • Install silt fencing adjacent to constructed roads and land that is cleared and grubbed.

Mining Phase

  • In wet processing, pump water shall flow back into the mining pit and shall not enter adjacent streams or wetlands.  Proper berms or levees shall be installed to ensure that pump water returns to the open pit.
  • Route runoff from stockpiles of overburden, sand and gravel back to the open pit and contain runoff using silt fencing, berms, vegetated buffers, etc.

Post-Mining Phase

  • Produce a slope of at least 4:1 (H:V) on the edge of borrow pits once mining has ceased.  Pit side slopes that are 4:1, or more gently sloping, improve wildlife access and revegetation capability, and are safer for users.
  • Recontour and resurface excavated areas using stockpiled topsoil and sand.  Restore soil profile to pre-mining conditions.  Stabilize topsoil by seeding.
  • Regrade constructed access roads and remove installed culverts if no longer needed.