Reclamation testing was carried out on 3 mineral exploration sites in Yukon: an alpine site at the Red Ridge property in the Whitehorse area, and 2 subalpine sites, a boreal forest site at the Nucleus property in the Carmacks area, and a site in moist permafrost at the Hawk propeerty int he Dawson City area.

Thesis written towards the degree of Bachelor of Applied Science. Petrographic and mineralographic data collected from the Williams Creek property, central Yukon, are presented which describe the host rock, mineralization and alteration and relationships between them. A copy of this thesis is available online at https://emrlibrary.gov.yk.ca/theses/Abbott_g_1971.pdf. A copy is available at the EMR Library - QE195.A22 1971.

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.

Cambrian (?) schist and phyllite of the Anvil Range, Yukon, host three large stratabound lead-zinc deposits: Faro, Vangorda, and Swim. Because geological exploration is limited by a thick cover of glacial overburden, geochemical techniques were tested in the area. These include bedrock sampling for primary halos and geochemical marker horizons, and glacial overburden sampling for secondary dispersion patterns. Multi-element geochemistry of bedrock indicates that the schist and phyllite are not distinctive in one or any combination of the trace elements analyzed. However, some younger rocks are enhanced in various elements: amphibolite in Ni, Cr, Co, and Cu; rhyolite in Pb and Sn; and granite in Sn. Despite presence of glacial overburden, the trace element content of bedrock is reflected in soils. Soils overlying magnetic greenstones are enriched in Ni and Cu, whereas soils overlying granite are slightly enriched in Sn content. Detailed bedrock, overburden and soil sampling at the Faro deposit reveals that primary Pb, Zn, Mo, and Ba halos exist about the ore zone. Mo parallels the visible alteration envelope, but Pb and Zn extend into the hanging wall and the footwall. Ba extends into the hanging wall but is not detected in the footwall. Secondary dispersion patterns are primarily related to the proximity of the Faro ore zone and type of parent material sampled. Till deposits have higher background and threshold values for Cu, Pb, and Zn than those of glaciofluvial deposits. Bath Pb and Zn distributions in overburden delineate the Faro #2 ore body; Zn extends to surface whereas Pb, in some cases, does not. This is a reflection of the type of overburden sampled. In general, Zn is the more consistent indicator of ore. The Zn anomaly is primarily hydromorphic in origin, cxZn having higher anomalous/threshold contrast than total Zn (11.1 for cxZn vs 4.8 for total Zn). The nature of the Pb anomaly is not understood. This thesis is available online at https://open.library.ubc.ca/cIRcle/collections/ubctheses/831/items/1.0302661. A copy of this thesis is available at the EMR library – TN27.Y8 M677.

This project involved the collection of moss mat samples from sites throughout Yukon. Sites included: Laura Creek, which drains Brewery Creek gold deposit; Logjam Creek, draining the Logtung tungsten and molybdenum occurrence; Williams Creek which drains the Williams Creek copper deposit; the Vancouver Creek placer drainage; and Eldorado Creek in the Klondike goldfields.

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.

Disturbance of frozen ground, through placer mining activities, may lead to slope failure. A stockpile of frozen overburden has recently begun eroding from the formation of a runoff channel. A large cut, approximately 300 metres long and up to 50 metres deep has been created adjacent to Gold Run Creek, a heavily mined area southeast of Dawson City. This stockpiled overburden has been in place for several years and has revegetated with several species of mature willows (age dated to 15 years). Either due to heavy rainfall or climate change, melting has commenced in the stockpile resulting in the formation of a runoff channel. This has increased in size and slope failure continues to enlarge the cut. Laberge Environmental Services conducted a reconnaissance survey of the site in July 2003, to assess the site with the purpose of exploring ways of halting the slope failure and stabilizing the disturbed section of overburden. Several bioengineering techniques have been suggested to assist in controlling the erosion.

A test of ground penetrating radar (GPR) was conducted on 10 placer deposits throughout the Yukon in March 1993. At each site, profile surveys were conducted near known depths to bedrock (drill holes, shafts or excavations), overburden GPR velocities were measured with common mid-point (CMP) velocity surveys and overburden resistivity was measured with horizontal loop electromagnetic (HLEM) resistivity soundings. Survey sites were located in frozen deposits in unglaciated terrain, in thawed deposits in glaciated terrain and in frozen deposits in glaciated terrain. In frozen unglaciated deposits in the Klondike and Moosehorn areas, GPR penetration varied from 10-28 m and averaged 19 m. Signal attenuation in thawed black muck and scattering within boulder layers limited penetration at two sites to about 10 m. The weathering of phyllitic and schistose rocks to clay enhances bedrock reflections; weak bedrock reflections were recorded due to a lack of dielectric contrast in deposits underlain by resistant bedrock. GPR performance is enhanced by surveying during winter or late spring when the zone of seasonal thawing is thoroughly frozen. Under optimum conditions, strong continuous bedrock reflections were recorded over distances of several hundred metres and accurate bedrock mapping was possible with a minimum of confirmatory drill holes.

Results are given of a geophysical test survey made at three localities on the Newcastle coalfield in August, 1952, to determine whether intrusive doleritic dykes could be located by the magnetic method. Knowledge of the position of the dykes would assist in planning the lay-out of underground workings and of surface roads. The results showed only slight variations of the magnetic field, but some weak anomalies of less than 100 gammas were recorded. The position of these anomalies coincides with the inferred position of the basic dykes near the surface. The variation in the shape of anomalies suggests non-uniformity of the magnetic properties and shape of the dykes. The magnetic method might be helpful in determining the position and extent of the dykes beyond the areas where they are known, but supporting evidence from other geophysical methods such as the gravity of electric resistivity methods may be needed to verify the magnetic results.