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.

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.

In the fall of 2001, live willow cuttings were used for stabilizing an erosion gully on a permafrost slope at Noname Creek in the Big Creek drainage. These structures (gully breaks and pole drains) were upgraded in the fall of 2003 and the early spring of 2004. In the early summer of 2004, the Noname Creek valley was burned in a wildfire. In order to assess the effects of this fire on the erosion control structures, the site was revisited in the summer of 2005. The black spruce forest on the slope above Noname Creek had been completely burned. Although the above ground sections of the pole drains and gully breaks had been scorched, the structures remained intact and most of the lower cuttings were sprouting new growth. Falling trees had damaged a few of the structures. The willow cuttings staked in the gully between the structures had also been scorched. Although many of these staked willows were apparently dead, the older ones (staked in 2001) were sprouting new growth at ground level. It is expected that the erosion control structures, although partially damaged, will survive and continue to function. It is also anticipated that the flow of water in the gully will increase as a result of the escalated melting of permafrost on the slope above Noname Creek.

This study was first conceived as an attempt to document the processes undertaken for the Brewery Creek Mine (referred to as Brewery Creek in this report) in the Yukon Territory and provide a description of the lessons learned from this process. The hope is that this report will be used in the future as a tool for regulatory authorities, assessors, resource development companies, and First Nations for analyzing and planning resource development projects. This report provides an analysis of some of the aspects of the first heap leach mine north of 600 from planning through to post-closure monitoring, start to finish by comparing expectations and predictions versus reality and the lessons learned through the entire process.

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.

not_specified

In July 2009 we re-visited the re-vegetation experiments, which had been set up on tailings in the period 2003-2006. The three experimental sites are at Mount Skukum, United Keno and Wellgreen. The experiments consisted of either seeding the tailings with various populations of the tufted hair grass and/ or with stratified (cold temperature treated) seed of the shrub soapberry, or making transplants of the same two species. The treatments included the addition of compost from the City of Whitehorse, addition of fertilizer as 7:7:7 pellets, addition of organic matter as sheep manure, peat or woody debris from on site and, in the case of Wellgreen, a lime addition to overcome the strong acidity. The results are striking and illustrated in the Plates 1-15. Data of performance and flowering success are shown in the Tables, as are chemical analytical data in the Figures and Tables. Plots set up in 2003 provide a nucleus for effective re-vegetation, having survived for 6 years. The success of the seedings and transplants at Mount Skukum and United Keno was good, while that at Wellgreen was very poor. Wellgreen has suffered flooding with washing out of plots and washing out of the neutralizing lime. Nevertheless, in compost additions plots at Wellgreen, set up in 2005 and 2006, a small amount of re-vegetation and survival has occurred, especially in the wetter areas near the tailings pond.

not_specified

URL: https://geoscience.data.qld.gov.au/dataset/cr090574 PL 276, QGC WOLEEBEE CREEK 122, WELL PRODUCTION EXTENDED TESTING REPORT FOR PERIOD 19/2/2014 TO 19/2/2015

Measurements of Chromium collected at Coyote Pumping Plant - Morgan Hill. Currently collected twice a year, previously collected quarterly. Access further information for this data set by contacting Bureau of Reclamation, California-Great Basin Region, Environmental Affairs Division (CGB-157). See ResultAttributes for STAFF_GAUGE, SMPL_DEPTH, SMPL_CATEGORY_NAME, METHOD_CODE, RESULT_RL, RESULT_RL-UNIT_STD_NAME, RESULT_MDL, RESULT_MDL-UNIT_STD_NAME, USBR_QA_SUBTYPE_NAME, USBR_QULFR_DESCRIPTION. STAFF_GAUGE is the water height in decimal feet measured by gauge (e.g., 15.2). SMPL_DEPTH is the vertical depth at which sample is collected (e.g., 0 - 15 cm). For water samples: depth below water/air interface. For sediment and soil samples: depth below water/solid or air/solid interface. SMPL_CATEGORY_NAME is the category type of sample (e.g., Composite). METHOD_CODE is the name of method used to obtain result (e.g., EPA 200.8). RESULT_RL is the result reporting limit (accounting for dilution) (e.g., 0.02). RESULT_RL-UNIT_STD_NAME is the unit associated with RESULT_RL (e.g., mg/L). RESULT_MDL is the result method detection limit (e.g., 0.007). RESULT_MDL-UNIT_STD_NAME is the unit associated with RESULT_MDL (e.g., mg/L). USBR_QA_SUBTYPE_NAME is the quality control type of the sample (e.g., USBR_BLANK_SPIKE). USBR_QULFR_DESCRIPTION is the quality assurance description (if any) (e.g., Result may have a high bias.).