4
at the drill site. New drill site surface disturbance would be kept to the minimum necessary for
safety.
Roads.
Road construction will be implemented using a Cat D8L or equivalent. The planned
roads would have a disturbance width of between 12 and 18 feet (15 feet on average),
depending on slope, with waterbars installed as needed. Every effort would be made to keep
road grades at ten percent or less unless steeper grades are necessary for short pitches.
Roads will be rerouted around trees where possible. Trees that would need to be removed
would be stacked on the uphill side of the road for salvage, unless otherwise directed by the
Forest Service. Slash from the trees will be stockpiled adjacent to the uphill side of the road and
will be spread over the reclaimed road during reclamation.
When drainages must be crossed with a road, BMPs would be followed to minimize the surface
disturbance and erosion potential. No culverts would be installed. Blasting is not anticipated for
road construction. Routine road maintenance may be required and would consist of smoothing
ruts, filling holes with fill material, grading and re-establishing waterbars when necessary.
Where practicable, methods to exclude public access to exploration roads would be utilized.
Such methods would include, but are not limited to, posting signs, partial reclamation, and
construction of buck and rail fence sections. All sign posting would meet USFS approval and the
standards set forth in the Manual on Uniform Traffic Control Devices (MUTCD).
Trenches and Bulk Sampling.
Trenches may be excavated to uncover rock for geologic
characterization. The trench excavation would average 5 foot in width and 6 feet in depth. The
spoils piles would be placed on the uphill side where practicable so the trench would recover
any displaced material. The overall footprint at any section along a trench including the spoils
piles would average 25 feet in width (5 foot wide trench with 10 feet of spoils on each side).
There may be between 19,000 and 20,000 feet of trenching excavated during the life of mine
activities. Bulk sampling may include the collection of excavated material placed into 55 gallon
drums for transport off site. The bulk sample would be collected using a backhoe from a road
cut or trench and no additional disturbance beyond the road cut or trench would occur. The
trenches would only be open long enough to map and sample. The trenches would then be filled
and capped with stockpiled soil.
1.3.3 Drilling
Both reverse circulation (RC) and core rigs will be utilized. Up to five drilling rigs could be
operating at one time. RC drilling utilizes a solid bit (usually tri-cone) to produce a hole that
delivers rock chips to the surface for subsequent analysis. RC drilling ideally produces dry rock
chips, as large air compressors dry the rock out ahead of the advancing drill bit. Reverse
circulation is achieved by blowing air down the rods, the differential pressure creating air lift of
the water and cuttings up the inner tube, which is inside each rod. The cuttings reach the bell at
the top of the hole, then move through a sample hose attached to the top of the cyclone. The
drill cuttings travel around the inside of the cyclone until they fall through an opening at the
bottom and are collected in a sample bag. Although RC drilling is air-powered, water is also
used to reduce dust, keep the drill bit cool, and assist in pushing cuttings upwards and out of the
hole. Nontoxic drilling muds are mixed with water and pumped into the rod string, down the
hole. This helps to bring up the sample to the surface by making the sand stick together.
Occasionally, super-foam is also used, to bring all the very fine cuttings to the surface, and to
clean the hole. When the drill reaches hard rock, a collar of metal or PVC pipe is put down the
hole around the rods. Collaring a hole stops the walls from caving in and bogging the rod string
at the top of the hole.
