The Brewery Creek property is a low grade oxide gold deposit hosted by syenitic intrusive rocks in the south Klondike area. The deposit apears to be structurally controlled by a low angle fault which may be part of the Tintina fault system. Drilling to date has proved up several million tonnes of mineralization grading approximately 2.5 g/t Au.

In order to determine which shrub species might be useful in revegetating Yukon mine sites at the time of closure, eleven species of shrubs were transplanted at three open disturbed sites at the Brewery Creek Mine in the Central Yukon in the fall of 2000. These sites included a steep north-facing slope, a steep south-facing slope, and a lower nearly level area. All three of these areas had been recontoured and seeded in 1996-97, and there was a thick growth of grasses and clovers at the time the shrubs were planted in 2000. To determine if this thick growth interfered with the survival of the newly planted shrubs, the grasses and clover were first removed from one-half of each of the test plots. Six years after the shrubs were planted, it appears that black spruce and Alaska birch are the most successful species transplanted on the north-facing site, trembling aspen and Alaska birch the most successful on the south-facing site, and dwarf birch, prickly rose and trembling aspen the most successful on the nearly level site. The planting of willow stem cuttings was not successful. After six years, the previously cleared half of each plot was once again covered with a thick growth of seeded and naturally occurring plant species. The clearing of vegetation before the transplanting of shrubs does not appear to have much of an effect on the ultimate survival and growth of the transplanted shrubs.

Two MERG-sponsored mine reclamation projects were surveyed during the summer of 2002. These included the Brewery Creek Mine where local shrubs were planted in large open areas at the mine site in 2000, and Noname Creek near Big Creek west of Carmacks where, in 2001, live willow cuttings were used at an abandoned placer mine to stabilize an eroding gully in permafrost. Because the effectiveness of reclamation projects such as these can only be determined after several year of observation, the two mine sites were revisited in 2002 to record the successes and failures of the experimental work and to make suggestions on where improvements can be made.

The Brewery Creek mine is a bulk tonnage gold deposit located 57 km east of Dawson City, in central Yukon, within the foothills of the Ogilvie Mountains along the northeastern boundary of the Tintina Trench. High-level fracture-controlled gold mineralization is hosted within Cretaceous monzonite sills and Devonian Earn Group siliciclastic rocks of the Selwyn Basin. Structural controls include northeast and southeast sub-vertical shears bounded by moderately south-dipping, southeasterly-extending listric normal faults; listric faulting and sill emplacements are localized along pre-existing graphitic thrust faults. Gold occurs as sub-micron particles in solid solution with pyrite and arsenopyrite as growth bands around larger sulphide grains that are disseminated within fine quartz veinlets. The open-pit heap leach operation produces 75,000 - 80,000 ounces annually, with a stripping ratio of 1.5:1 and a cash cost of US$200/oz or less. The mineable reserves at the end of 1997 stood at 13.3 MT @ 1.44 gpt (613,000 oz).

Brewery Creek is a bulk tonnage gold deposit 76 km east of Dawson. The economically important intrusive bodies are the semi-conformable sills of quartz monzonite which intrude into upper Road River and lower Earn Group (dominantly clastic sedimentary) strata. Low angle faults, inferred to be thrust faults, appear to have controlled the emplacement of the Cretaceous quartz monzonite sills which host most of the gold mineralization.

A reconnaissance-level study of post-mining hydrogeochemical conditions was carried out at the Brewery Creek gold deposit within the Tintina Gold Province. The deposit is characterized byepizonal mineralization with a consistent arsenic-gold-mercury-antimony geochemical signature. Surface discharges and seeps in the area are naturally alkaline (pH=7.6-8.2), Ca-HCO3 ¯-SO4²¯ waters. Upstream from the recognized mineralization, waters contain <3 ¿g/L As and <1 ¿g/L Sb. Water samples immediately downstream from the ore bodies show maximum concentrations of 18 ¿g/L dissolved and 47 ¿g/L total arsenic, and 18 ¿g/L dissolved and 21 ¿g/L total antimony. Two kilometres below the mineralization, on lower Laura Creek, arsenic concentrations are diluted to background levels of <3 ¿g/L, and antimony levels are still slightly elevated at 9-10 ¿g/L. Comparison with hydrogeochemical data from Donlin Creek, an undeveloped epizonal deposit in Alaska, indicates that elevated concentrations of a few tens of ¿g/L arsenic and antimony are typical of waters draining such gold systems, regardless of their state of development. In addition to their usefulness for the construction of geoenvironmental models, these data also provide information for establishing exploration programs utilizing water sampling.

The Brewery Creek gold mine (13.3 Mt @ 1.44 g/t Au) is a bulk tonnage, heap leach operation located 57 km east of Dawson City, Yukon. The deposit lies on the northeastern side of the Tintina Fault and within Selwyn Basin. Gold mineralization is hosted by intrusions of the mid-Cretaceous Tombstone Plutonic Suite (TPS), and Silurian to Carboniferous clastic metasedimentary rocks of the Steel Formation and Earn Group. The sedimentary rocks are faulted and variably folded, however they display poor cleavage development. The TPS intrusions are also faulted and contain rafts of argillaceous sedimentary rock. No regional ductile fabrics were observed to crosscut the intrusions. Five phases of intrusion have been recognized; these are `raft monzonite, feldspar porphyry (FP1), biotite monzonite, a second phase of feldspar porphyry (FP2), and a pyroxenite. The most important feature at Brewery Creek is a linear zone of monzonite intrusions, faulting and mineralization termed the Reserve trend. This zone trends west-northwest and has a moderate dip to the south. A number of stages and orientations of faulting have been identified along the Reserve trend; lithological relationships suggest a substantial amount of vertical movement occurred post-TPS emplacement and pre- to syn-mineralization.

In September 2000, eleven shrub species were planted in experimental plots at three different areas of the Brewery Creek Gold Mine near the Klondike River. All of these shrub species naturally grow in the mine area. The purpose of this project is to find out which of these shrub species may be useful for revetating the large open areas at the mine site, after the mine closes. It is anticipated that this information will also be useful when revegetating other mine sites in the Yukon. The three sites chosen for these experiments are a steep north-facing slope, a steep south-facing slope, and a lower, nearly level area. The shrubs were planted in six plots at each of the three sites. All three areas had been graded and seeded in 1996-97, and there was a fairly thick growth of grasses and clovers at the time the shrubs were planted. To determine if this thick growth interfered with the survivial of the newly planted shrubs, the grass and clover was first removed from one half of each plot.

An Integrated Regulatory Regime for Yukon Placer Mining was the final report of the Yukon Placer Implementation Steering Committee, submitted to the Minister of Fisheries in 2005. Under a proposed new management regime, the Yukon's placer mining industry will be managed through an adaptive management framework, with the aim of striking a balance between maintaining a viable placer industry and the protection and conservation of aquatic ecosystem integrity and fish populations. The effectiveness of the regime at achieving this balance will be monitored and assessed with appropriate adjustments to the requirements as required. The report recommended that a number of protocols be prepared and implemented in order to monitor the effectiveness of the new management system and among these is one with the primary objective of assessing and monitoring watershed health. A draft Watershed Health Monitoring protocol was completed July 1, 2006, and is currently being reviewed and considered by first nation, territorial and federal government agencies, industry and conservation organizations, and the general public. The draft protocol aims to provide for a process to help assess how effective the new management regime is for maintaining watershed health and to generate monitoring results that will be used to guide the adaptive management framework assessment and adjustment phases. After consideration of a number of methods, the Reference Condition Approach (RCA) was selected for assessing and monitoring watershed health under the draft protocol. There were a number of reasons for this choice: - It is the most robust of many biomonitoring methods - It is the basis of regional programs in Canada (it is an accepted design under the federal Environmental Effects Monitoring program), and programs in other countries, several USEPA programs in the United States, national programs in Australia and the United Kingdom, and has been adopted under the European Water Directive. - An RCA program has been underway in the Yukon for a number of years that could be immediately applied to the placer mining areas and augmented by future fieldwork. When the draft protocol was in preparation in the spring of 2006, meetings were held among those already conducting some type of stream sampling program associated with the Yukon placer mining industry. This included The University of Western Ontario, the federal Department of Fisheries & Oceans, and Environment Yukon Fisheries section. These three groups agreed to collaborate and carry out RCA sampling in 2006 in a manner consistent with that provided for in the draft Watershed Health Monitoring Protocol in order to "test drive" the methodology and assess its effectiveness at achieving the new management regime's objectives. Follow-up Geographical Information System March, 2007 3 (GIS) data collection and data analysis were also carried out as provided for in the draft protocol. In addition, reference sites were subjected to simulated impacts and then the RCA models were applied to these impacted sites in order to demonstrate the ability of the RCA models to detect a known degree of disturbance in streams.

An extensive heap leach field test was conducted during the 1993-1994 winter season at Carmacks, Yukon Territory. The test itself utilized an approximately 5-m-diameter crib loaded with composite ore from the northern (higher grade) end of the Williams Creek deposit. The ore was stacked to a total height of 7 m, including one meter of ore atop the emitter system. This matched the commercial heap height planned for Williams Creek at the time the test was started. By insulating the side walls of the crib, lateral heat flux was minimized. Thus, the crib replicated an interior segment of the commercial heap. Leaching was done at a flow rate that matched those commonly used in industry. Leachate temperature was about 21°C, a level achieved with no external heat input other than normal process heat transferred from electrowinning to the leachate via solvent extraction. An analysis of the test results showed that the winter conditions at Carmacks were quite typical of those expected at the mine site. Conditions included ambient temperatures below -40°C and an average temperature of -13°C. In terms of leachate flow to and from the crib, the test ran continuously from late September through mid-February. In spite of some flow system problems, leaching continued unabated. There was no freezing in the interior of the crib or in the solution reservoir at the bottom. Freezing was limited to the insulating ore over layer and a few isolated points high in the crib near the outer walls. The test clearly demonstrates that year-round heap leaching of Williams Creek ore is practical. The heap appears to be adequately insulated by a 1 m ore layer on top of the emitter system. Normal process heat should be sufficient to maintain a leachate return temperature of approximately 20 degrees Celcius at the heap. However, provisions for some supplemental heating in the commercial operation may be desirable. This would permit recycle of the heated solution if electrowinning goes off-line or if there is a long run of exposed leachate pipeline back to the heaps.