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Our
Expertise . . . |
Gold Projects
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Asamera Minerals (U.S.), Inc. Wenatchee, Washington, USA
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Barrick Goldstrike Mines, Inc., Elko, Nevada, USA
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First Miss Gold, Inc., Golconda, Nevada, USA
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Indepdendence Mining Company, Elko, Nevada, USA
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LAC Minerals, Ltd., Beatty, Nevada, USA
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Newmont Gold Company, Carlin, Nevada, USA
Asamera Minerals (U.S.),
Inc., Cannon Mine, Wenatchee, Washington, USA
The Cannon Mine is a multi-lift benching cut-and-fill operation
utilizing high-strength backfill to allow full recovery of the gold
mineralization. AAI has been involved in the design of mining operations at
the Cannon Mine since the development stage in 1982 through closure in the
early 1990s. Geologic and rock mass characterization data was evaluated to
provide design recommendations for bid specification on the construction of
the access decline and shaft facility. Mine layout and stability evaluations
were performed to develop recommendations for stope and pillar dimensions,
and to specify the strength of cemented backfill. High-strength backfill was
required for stable conditions during pillar recovery and to limit surface
subsidence. Production and backfilling sequences were established to
coordinate the mine operations and optimize stability. Design of the
backfill material included evaluating material resources, generating mixture
specifications, and testing of different candidate mixtures. Different fill
plant and emplacement systems were evaluated, with detailed cost estimates
developed. Subsidence was not permitted so the fill placement
techniques were developed to minimize ground movement. Projects completed
during mining and mine closure included monitoring ground movement, analysis
of rock backfill interaction, and assessment of mine closure plans.
Field personnel assisted Asamera geologists in structural characterization
of drill core during the early exploration phases of the project. AAI
personnel operated the Boyles Brothers wireline core orientation system to
develop absolute orientation of structural features and shears during coring
operations. The data, along with rock structural logging data, were used to
develop recommendations for rock support systems required in construction of
the main decline and shaft excavations.
Barrick Goldstrike Mines, Inc., Rodeo Underground Project, Elko, Nevada, USA
AAI conducted a backfill study for the Rodeo Underground Project
for Barrick Goldstrike Mines. The project included a design review to assess
the strength required for cemented rockfill and mix specifications to
achieve the desired backfill strength for placement in drifts and stores for
an underground mine under development in northern Nevada. In addition, AAI
compiled test data from mix samples prepared and tested by a commercial
laboratory.
Assessment
of the backfill strength requirements was accomplished through numeric
modeling utilizing a two-dimensional elastic model incorporating properties
of waste rock available at the mine site along with characterization data (RQD
and RMR) representing the condition of the rock forming the stope walls and
back. Mix designs were proposed to achieve the strength of backfill
indicated by the analyses. An interim report was issued regarding the
backfill strength study. Additions of fly ash and other commercial
admixtures were also incorporated into mix designs to evaluate the influence
of these additives. The mine employs the backfill design comprised of
crushed and sized waste rock used at the adjacent Meikle Mine.
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First Miss Gold, Inc., Getchell Mine, Golconda, Nevada, USA
For this underground cut-and-fill gold mine, AAI performed a
ventilation survey to determine friction factors and airway resistances. Air
flow quantities for Phase I mining were calculated based on the equipment
fleet. A network model was prepared using MFIRE and WINDY, and used to
assess air flow distribution. Heat transfer calculations using MFIRE,
calibrated via a temperature survey, were used to determine the capacity of
a mine air heater to prevent freezing in the stopes.
Independence Mining Company, Murray Mine/Jerritt Canyon Project, Elko,
Nevada, USA
AAI began consulting services in 1993 at two underground mines at
the Jerritt Canyon Project: West Generator and Murray Mines (previously
called New Deep). For the Murray Mine, AAI conducted geotechnical
evaluations of the data collected during the exploration drilling. Based on
the data, the rock mass quality was estimated for each core run in the
hangingwall and mineralized zones of each hole. Structural stability of
bench and cemented fill-and-drift and cemented fill mining methods were
evaluated for various probabilities of occurrence of the rock quality and
rock strength parameters. Extreme variations in rock quality and distinct
zonation of the assays has led the Murray Mine designers to delineate the
deposit into zones. Both bench-and-fill and drift-and-fill mining methods
are being applied at the Murray Mine. AAI developed instrumentation plans
for ground monitoring of load transfer and ground movements in critical
areas and continues to assist in rock mechanics issues at the Murray Mine.
AAI also conducted design and strength tests of various cemented fill mixes
using readily available material from the site.
Independence Mining Company, South Saval
Extension/Jerritt Canyon Project, Elko, Nevada, USA
Preliminary geotechnical evaluations were conducted by AAI from
exploration drill core data for the proposed underground extension of the
Saval Pit. Approximately 20,000 ft of decline and mine level development
mining was planned to achieve extraction of 2,500 tons per day at full
production. Anticipated ground conditions were compared with two other
operating underground mines on the property, West Generator and Murray,
where bench-and-fill and drift-and-fill mining methods were employed. The
suitability of these mining methods to the South Saval Extension was
evaluated based on the comparisons of the rock quality and strength
parameters.
LAC Minerals,
Ltd., Bullfrog Mine, Beatty, Nevada, USA
AAI developed recommendations for design of the underground
ventilation system for multilevel mechanized cut-and-fill mining at the
Bullfrog Mine. Air requirements for the diesel equipment were used to
establish specifications for face and total mine air quantities. Network
analysis of long duct systems for face ventilation was performed to assess
leakage impacts on duct and fan specifications. Network analysis was
performed to estimate the full mine resistance for main fan selection.
Trade-off calculations were also performed to establish the dimensions of
exhaust boreholes.
Newmont Gold Company, Deep Star Project,
Carlin, Nevada, USA
AAI designed the main and auxiliary ventilation for this
proposed underground gold mine. The project involved a complex ventilation
network with many dead-end headings to be mined using a large fleet of
diesel equipment. Volume requirements were determined including estimated
leakage losses. Network modeling was performed using the program MTU to
determine fan pressures and to locate regulation devices. Specifications
were prepared for main exhaust fans, development fans, auxiliary fans, and
ducting. Capital and operating costs were developed for the ventilation
system. A detailed analysis of mine air heating require-ments was also
performed using local meteorological data.
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AGAPITO
ASSOCIATES, INC.