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LLynn Sheffield, Environmental Coordinator
at Jerritt Canyon, holding a three-week old Northern Goshawk.
Jerritt Canyon personnel, in collaboration with the US Forest
Service and Boise State University, have been studying this
sensitive species in one of the longest running studies of the
goshawk in North America. The study has provided much useful
information about the rare raptor.
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| Lynn Sheffield, Environmental Coordinator at
Jerritt Canyon, monitoring the H-pit wetlands which were established
to counter the disturbance caused by mining to existing wetlands.
This site is about 20 acres in size and allows for a potential
wetland of about five acres. |
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Fish population survey along the North Fork
of the Humboldt River at the Big Springs mine site. The survey work
was a collaboration of AngloGold personnel, Nevada Division of
Wildlife, Nevada Bureau of Health Protection Services, the U.S.
Forest Service, and Chadwick Ecological Consultants. The population
survey work indicated that there had been no adverse effects from
the mine to a threatened trout species living in the river.
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A bulldozer is used to create an exploration
track for drill rigs to access the desired drill locations.
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The original slope profile is restored using
an excavator to cutdown the upper slope and pull material up from
the lower slope.
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Once the slope is restored, the area is
replanted with an indigenous grass seed mix, fertilised and left to
recover. Old exploration tracks are still visible on the sides of
the hill, but are gradually colonised by neighbouring vegetation.
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Case studies
North America |
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| 7.10 Protecting for the future –
biodiversity programmes in North America |
| An integral part of managing operations at
AngloGold?s North American mines are the provisions that are in
place to protect the biodiversity of areas that have been mined or
are adjacent to mining. In addition to complying with all relevant
legislation and employing best practice techniques for environmental
management and reclamation, the company expends great effort in
ensuring that the areas mined are returned to the same, or better
land use than before mining. As far as biodiversity is concerned
this means the following: |
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Revegetation activities are undertaken
based on biodiversity concerns, including the use of
predominantly native species in the seed mix to revegetate
reclaimed areas, collecting indigenous seeds from woody plants
such as bristle cone and aspen, planting wild flowers to provide
a food source for humming birds, bees and other insects, and
undertaking an aggressive weed control programme; |
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The installation of rock and brush pile
habitat for indigenous species; |
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Provision of assistance to studies of the
broad ecosystems used by the Northern Goshawk, thus reducing the
need for designation and protection under the Federal Endangered
Species Act; |
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Efforts to reduce or limit the impact on
the Lahontan Cutthroat Trout, a fish species protected under the
Endangered Species Act; |
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Interface with the Nevada Division of
Wildlife for continuing deer and sage grouse mitigation
activities; |
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Mitigating the loss of wetlands by
developing comparable and better wetlands after mining; and |
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Creating controlled site access for the
public, so improving native vegetation areas and creating a de
facto wildlife reserve. |
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| 7.11 Innovative reclamation of exploration tracks and haul roads |
Reclamation of mining land situated in hilly or
mountainous terrain is often a daunting task. In North America,
AngloGold staff have developed some novel approaches to reclamation
of exploration tracks and mining haul roads. The Burns Basin area in
the Independence Mountains, in the state of Nevada in the United
States, is a beautiful area, with rocky outcrops and stands of aspen
trees, home to deer, elk, mountain lion and the rare Northern
Goshawk. The Burns Basin was part of the Jerritt Canyon mining
project in Nevada. AngloGold?s interest in Jerritt Canyon was sold
to Queenstake Resources in early 2003, but the mine was part of
the AngloGold stable when the reclamation programme was initiated in
2001.
Exploration drilling is required to prove the existence of a
gold-bearing ore-body. With mountainous terrain comprising a large
part of the mining lease, the construction of tracks, criss-crossing
the hills, was necessary for drill rigs to access the desired drill
locations.
Unrehabilitated, these tracks would leave a damaging scar on the
hilly landscape. However, impressive rehabilitation of these tracks
has been achieved, relatively inexpensively, using an excavator to
remove the tracks. The area is then replanted with an indigenous
grass seed mix, fertilised and left to recover. The photographs show
how the original profile of the slope is restored by cutting down
the upper slope and pulling up material from the down-slope.
Having proved the existence of a viable gold-bearing orebody, the
mine is planned and haul roads are constructed to gain access to the
mine pit. These haul roads must be capable of carrying 100 tonne
dump trucks and are therefore a lot bigger than the exploration
tracks.
Jeff Campbell, Senior Environmental Coordinator, explains how haul
roads are rehabilitated: ?The topography in the Jerritt Canyon
Project area often makes full re-contour of haul roads a challenging
undertaking. The existing slopes along the Burns Basin haul road
range from 30? to 50?. Such steeply sloping areas used to receive
only a partial re-contour, leaving a small portion of the cut slope
unreclaimed; this was because of the high costs of re-contouring
steeply sloping land. Previous experience at Jerritt Canyon has
shown that haul road reclamation on moderate to steep slopes can be
done in the range of US$12 to US$18 per linear foot (approximately
0.31 metres) of 80-foot (~25 metres) haul road.
However, the Burns Basin haul road was a special case. The haul road
is situated in the southwest portion of the Jerritt Canyon Project
at an elevation of 7,900 feet (2,400 metres). Even though the
approved reclamation plan for the haul road did not require full
re-contour of the road, our goal was to reclaim as much as possible
back to original topography. There were a number of reasons for
this, not least because this is a beautiful portion of the
Independence Mountains. Also, the Burns Basin haul road is situated
high on a ridge which can be seen from most portions of the drainage
basin area.Reclamation of portions of the primary haul road network
began in the late summer of 2001. Approximately 12,000 feet (~3.6
kilometres) of 80-foot wide (~25 metres) haul road was re-contoured
to the original topography and re-seeded. This project represented
the first significant attempt at the Jerritt Canyon Project for full
re-contour of haul roads in areas exceeding 30?? side slope while
keeping reclamation costs within a reasonable range.
The 2001 Reclamation Programme was awarded to a local reclamation
contractor in Elko, Nevada. After reviewing the project area and
discussing the reclamation goals with AngloGold?s Environmental
Resources Department at Jerritt Canyon, the contractor decided to
use two hydraulic excavators with two support dozers. The excavators
consisted of one Caterpillar 345B and one 365B along with two D8
dozers. The re-contouring process utilises the two excavators in
tandem, with one excavator on a lower bench reaching to the toe of
the fill slope and casting material to the second excavator on an
upper bench where a portion of the material is moved in a second
?pass? to a support dozer. Depending on the steepness of the
topography, two, three, and sometimes four ?passes? may be required
to retrieve material from the toe of the fill slope and redistribute
material to the top of the cut slope. One or two dozers proved
to be very effective in redistributing material brought up by the
excavators to achieve a full re-contour of the cut slope and for
final shaping of the re-contoured slope.
While this re-contouring technique is not a new one, the challenge is
to achieve a full re-contour while maintaining a cost effective
reclamation programme. However, these previous projects were not
done to full re-contour. The Burns Basin haul road was re-contoured to
original topography in areas of 30? to 50? side slopes for about
US$17 per linear foot.
Returning the land to its original contours represented only the
first step of the project. After completion of the re-contouring, the
entire area was broadcast seeded and fertilised in the fall of 2001.
The re-contoured slopes were fertilised with 350 pounds per acre of
inorganic fertiliser. Then, the reclamation seed mix, consisting of
22 species of grasses and shrubs, was broadcast and harrowed. In
addition, 2,500 aspen seedlings, grown from seed collected at
Jerritt Canyon, were planted in five areas along the Burns Basin
haul road where aspen had been removed during the construction of
the road. The aspen seedlings should accelerate the rejuvenation of
the aspen stands along the haul road reclamation.
In conclusion, Jeff points out that, even though overall cost was a
consideration during this project, the primary goal was to achieve
an aesthetically pleasing reclamation project in the Burns Basin
area. Cost effective implementation of any reclamation project is
enhanced when the contractor and/or equipment operator understands
the reclamation goal and strives to meet that goal through genuine
interest in the project and the final product. The steep slope
reclamation of the Burns Basin haul road demonstrates a successful
reclamation strategy, where neither the overall project economics
nor the final reclamation goal were compromised to achieve the
desired outcome. |
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