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Quarry Noise

Mining Operations Will Create Noise Levels That Will Affect People's Lives for Twenty Years

The Environmental Impact Report (EIR) for the quarry project describes noise that will be generated by on-going mining and processing operations.  This includes:

  • Grading and construction / widening of roads along the haul routes
  • Excavating and grading of the processing areas and sediment ponds
  • Constructing an access road into the quarry
  • Installing truck scales and a moblie quarry plant
  • Operations at the mobile quarry plant equipment consisting of jaw crushers, cone crushers, plate feeders, screens and conveyor belts
  • Clearing of vegetation and removal of topsoil and overburden and hauling these materials to on-site stock pile locations
  • Cutting quarry benches into the hillslope
  • Ripping materials from the quarry face and transfering materials to a mobile processing plant
  • Processing and sorting gravel
  • Loading materials onto/ off of trucks
  • Offloading of recycled materials imported to the plant
  • Powering the quarry by a diesel generator
  • Adding 200-400 gravel trucks per day to the county road system
  • Blasting rock up to twice a month

Blasting Noise

Nearest Residence Only 600 Feet Away

Blasting that would occur under the quarry site will generate airborne and groundbourne noise and vibration. This will include blasting rock from adjacent to the closed County landfill.  The expectation is that the quarry will conduct blasting once to twice a month with 20 to 25 detonations each time over the 20 to 30-year lifetime of the quarry with up to 275 pounds of blasting material per detonation.  It stands to reason there is going to be increased noise from this activity.

Truck Noise

The EIR stated that noise along Roblar Road prior to a quarry being built is generated only by car traffic, existing truck traffic and wind.  Residents living along Roblar Road told planning commissioners and the supervisors that the acoustics within the Roblar Valley influenced by the sloping hillsides and  daily winds are such that they can hear the conversations between bicyclists riding along the roadway. Adding 200-400 gravel trucks per day along Roblar Road and surrounding country roads is going to increase noise very significantly.

Residents along the haul routes are concerned truck noise will increase by drivers using Jake brakes. A Jake brake is an add-on engine brake for diesel engines that helps drivers slow their trucks on down hill grades and turns without having to apply the actual brakes. Due to the extreme heavy loads gravel trucks carry, drivers may frequently use their Jake brake to avoid costly wear and tear on the wheel brakes. The problem with this is that the engine add-on Jake brakes make a loud staccato noise that carries. The EIR says drivers'  use of Jake brakes will be "restricted" but does not state any quidelines or explanation for what that restriction will be. 

Hours of Operation
24 Hours a Day???

The quarry is approved to operate six days a week from 7 a.m. to 5 p.m weekdays and 7 a.m. to 4:00 p.m. on Saturdays. But, the County will allow it to be open until 10 p.m. without getting an exception AND the quarry owner already has applied for an exception to be able to be open 24 hours a day. We have not heard that this exception has been granted, but the mere possibility of it for nearby residents is a frightening concept. The noise impact to residents from hundreds of gravel trucks traveling along all the haul routes and mining operations will be significant and will last for 20 or more years!

Source: Roblar Road Quarry Draft Environmental Impact Report