The geology of the region consists of (?)Hadrynian to Paleozoic Snowshoe Group rocks. The Snowshoe Group is an assemblage of dominantly metasedimentary rocks within the Barkerville Terrane of south-central British Columbia. The metasedimentary rocks consist primarily of marble, quartzite and phyllite. In the Yanks Peak area these rocks comprise the Keithley and Harveys Ridge successions but further to the east they remain undifferentiated. Metamorphism of the region varies from chlorite to sillimanite and higher grade. Gold-bearing quartz veins occur only in greenschist facies rocks.

The mineralization of the Bertha showing consists of gold and associated pyrite in a quartz vein hosted by argillaceous quartzite. The Bertha vein is well exposed for a length of at least 61 metres at 1698 metres elevation in the northwest corner of the Old Timer claim (Lot 11337, 093A 030) and the northeast corner of the Bertha claim. The vein strikes about 015 degrees and ranges in width from 0.9 to 2.1 metres. The vein quartz is not fractured and very sparsely mineralized. The Bertha claim adjoins the Old Timer claim on the west.

The hostrock has been mapped as "Midas Formation" (Campbell, 1978; Geological Survey of Canada Open File Map 574) but was remapped as undifferentiated Snowshoe Group (possibly the Harveys Ridge succession) by Struik in 1988 (Geological Survey of Canada Memoir 421).

In 1954, Snowshoe Gold Mines Limited owned Lots 11332 to 11346. These fifteen Crown-granted claims are near the head of Luce Creek on the north side of the valley, due north of Yanks Peak. They were formerly known as the Jane group (093A 027). On their eastern side they adjoin the Jim group, and on the southeast the Midas (093A 035). In 1862, a quartz vein was discovered on ground which is now included in the Old Timer claim (Lot 11337, 093A 030). This, the first quartz vein found in the Keithley Creek district, was discovered by Thomas Haywood and Edward Jeffrey, who named it the Douglas vein. Later, it has been known as either the Haywood vein or the Arrastre vein. Haywood drove a 27-metre adit to intersect the vein below its outcrop and that an arrastre built on the ground was unprofitably worked by William Luce on quartz from the vein. In 1886, after Haywood's death, the ground was relocated by Veith and Borland, who cleaned out the old adit and shipped some quartz for a test. There is no record of work having been done for many years after 1887. The claims lapsed in the interval and were relocated by R. Reinhold in 1928. In 1933, the group was under option to Island Mountain Mines Company Limited, for which Reinhold drove a short adit on the south side of Luce Creek near the northeast corner of the Betty Fraction (Lot 11334, 093A 032). Reinhold and partners optioned the Jane group to F.M. Wells, who in 1937 organized Snowshoe Gold Mines Limited. The company built a camp and in 1938 began underground exploration which continued into 1939. The Old Timer property was idle in 1940, and in 1941 Pioneer Gold Mines of B.C. Limited took an option on the property and did some underground exploration. Work by the Pioneer company ceased in January, 1942, and since then no further work has been done. The main surface workings are on the Jane, Old Timer, and the Bertha. The workings are in two separate areas; one area includes the veins which constituted the first discovery and are on the Jane and Old Timer close to camp, and the other, lying about 366 metres to the north, includes several veins on the Bertha. The Jane claim adjoins the Old Timer claim to the south, and the Bertha claim adjoins the Old Timer claim on the west. The Camp, Intermediate and Lower adits are on the Jane claim; and the Lower and Upper Arrastre adits are on the Old Timer claim.

In 1981, Suncor Inc. optioned the Yanks Peak property from Zelon Enterprises Ltd. The property covers the Bertha showing and others. Exploration programs were conducted in the summers of 1981-82. In 1984, the exploration program included grid establishment, geophysical and geochemical surveys, and geological mapping.