REP35525

• Permit No: M1978305
• IBM Index Class Name: Report
• Doc Date: 5/18/2004
• Doc Name: Environmental Assessment
• From: Nat. Park Service
• To: DMG
• Media Type: D
• Archive: No

completed under Alternative B. A description of mining operations and reclamation that would
occur under Alternative B are provided in the following sections.
2.3. Description of Mining Operations
The basic operational procedures and equipment that would be used to mine the decomposed
granite and intermixed materials would be the same under both alternatives and would involve
drilling, blasting, crushing, and hauling of the crushed mineral material. These operations are
described below and apply to both alternatives. However, it should be remembered that the
extent of operations would be very limited under Alternative A and expanded both in duration
and extent under Alternative B. Table 2.5, Comparative Summary of Alternatives provided at
the end of this chapter, summarizes the main features of operations for Alternatives A and B.
Ripping, Drilling, and Blasting -Most of the decomposed granite material is soft enough to be
ripped by a bulldozer. Small areas of more competent rock need to be blasted to be removed.
The operator begins a new section of mining by ripping the material or by drilling holes about 12
to 15 feet down into the resistant mineral material, and blasting out benches. Blasting is
performed using ammonium nitrate-based explosives that are set into the shot holes. Benching
follows all Mine Safety and Health Administration requirements and results in the appearance of
steps along the face of the rock. Blasting is contracted out and currently occurs once or twice a
year, lasting a few days at a time. Under Alternative B, frequency of blasting may increase and
blasting may last up to 1 to 2 weeks, depending on market demands. Traffic is halted during
blasting by flagging cars and using appropriate signage. Explosives are not stored on site.
Extraction -- The loosened material is then pushed down slope to the stockpile(processing
I area using large bulldozers. The maximum operating range of the bulldozers on slopes is
approximately 26°-28 ° or 2:1 (horizontal:vertical). The material is then sorted by bulldozer or
loader into pit run (no processing), fines, oversize (rip rap), and material to be crushed and
screened.
Crushing and Screening -The crusher is a contracted mobile unit with screening equipment
and a stack conveyor. The crusher crushes the blasted rock into appropriate sizes for its
intended use. The crusher is diesel-powered and has air pollution controls and any required
permits, noise suppression, and a water spray to control dust. Crushers may not remain on site
for more than 90 days unless the Superintendent approves this in writing. Average crusher
~ production is 250 tons per hour.
Stockpiling/Scales -Once the mineral material is separated, crushed and/or screened, it is
conveyed to a stockpile and remains on site until it is loaded into trucks for transport off site.
Semi-portable truck scales are on the site for weighing material prior to transport.
Material Hauling -Various pieces of equipment are used to move material from one area to
another and to load material into trucks. These include wheel loaders, trackhoe/hydraulic
shovels, 25- to 65-ton bulldozers, scrapers, and dump trucks.
Off-site Transport -The stockpiled material is loaded into 10- to 22-ton dump trucks, which
exit the pit onto US 50 (both east- and westbound). Cars are not slowed or stopped as trucks
enter the highway. Current production that would continue under Alternative A would result in an
average of one to two trucks per day, with maximum truck traffic reaching 120 trucks on the
busiest days, while truck traffic under Alternative B could reach 120 trucks per day during the
highest production summer days, with an expected average of less than 40 trucks per day.
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