technical report on the nechalacho deposit, thor lake project ...

Lateral Development
The access decline will be driven from surface as a single heading for approximately 1,200 m,
thereafter, there will be multiple headings available with the two stope access drives and the
continuation of the decline to the fine ore bin discharge location. On the stope access levels the
individual stope access crosscuts will serve as muck bays during development, therefore no
additional allowance for muck bays has been included.
Scott Wilson RPA estimates that with 4.3 m (14 ft) steel there will be 3.65 m break on a given
round. In an average day on a single face advance the expected rate of advance is 1.5 rounds
in a 24 hour period for an advance rate of 5.4 m per day. With multiple heading advance the
rate for the same equipment is expected to increase to 7.3 m/d based on two shift operation.
With a 5 m by 5 m heading the 5.4 m of advance will generate 365 tonnes of rock which can be
hauled to surface by truck.
Ore encountered in the mine development and hauled to surface before the completion of the
underground crusher will be stockpiled on surface and then hauled back underground and
crushed using the main crusher.
Stope Production
The stope production cycle will start with development headings down the centre line of the
primary stopes. Each 5 m by 5 m round will generate 265 tonnes of ore. With primary stope
panels that are 150 to 250 m in length, each 5 m high primary stope cut will generate 33,000 to
55,000 tonnes of ore.
In order to reduce initial capital costs the first five years of production muck is planned to come
from the development and slashing of primary stopes, the completion of some primary stopes
(less than 15 m thick) and from breasting or benching of the initial primary stope cuts.
Primary stopes will then be mined using blind uppers long holes for stopes that are up to 20 m
thick. In areas where the zone is more than 20 m thick the ore will be extracted using sublevels
for access and by mining the stopes from the bottom up with fill between the sublevels before
extraction of the subsequent lifts.
Technical Report 43-101 – March 13, 2011 Page 18-16
Prepared by Avalon Rare Metals Inc.