The Ymir-Goodenough occurrence is located at 1372 metres elevation on the west side of Huckleberry Creek (north fork of Wildhorse Creek, a small south-flowing tributary of Ymir Creek), 5.6 kilometres northeast of Ymir. The former mill site and no. 10 level adit portal are located downslope to the southeast at an elevation of approximately 1060 metres.

The deposit is hosted by Lower Jurassic Ymir Group schist, argillite and quartzite. Felsic dikes (up to 1 metre wide) strike 030 degrees and dip 74 degrees northwest, crosscutting the hostrocks. Augite basalt flows and flow breccias of the Lower Jurassic Elise Formation (Unit Je1) (Rossland Group) occur just to the west and the contact with the Middle Jurassic Nelson Batholith is approximately 1 kilometre to the east.

Pyrite is disseminated in quartz veins and throughout the sedimentary rock. Mineralization is confined to a shear zone trending northeast at 065 degrees with a 60 to 70 degree dip to the northwest. The shear crosscuts the sedimentary stratigraphy, which strikes 035 degrees with a 70 degree northwest dip. Economic mineralization occurs as lenses with an easterly pitch and frequently contains narrow bands or inclusions of argillite.

The main ore zone, the Bonanza shoot, is approximately 146 metres long by 3 to 12 metres wide, and averages 4 metres in width. This zone was mined to a vertical depth of approximately 153 metres. Ore minerals consist of pyrite, galena, and sphalerite with trace chalcopyrite disseminated in the sphalerite. Near the surface, where the vein is oxidized, cerussite and free gold are common. Below 150 metres depth quartz becomes more prominent and at approximately 300 metres ore mineralization is confined to streaks within the quartz. Ore material gradually decreases along strike to the east but to the west the vein is terminated by a fault. The Protection (MINFILE 082FSW073) occurrence may be the western extension of the Ymir vein; the latter is much wider although other characteristics are similar.

The hostrocks are crosscut by lamprophyre dikes and numerous faults and are complexly folded; however, there is no evidence of granitic intrusives associated with the ore zone as is common at some nearby deposits. The Tamarac (MINFILE 082FSW072), Protection (MINFILE 082FSW073), Ymir, and Good Hope (MINFILE 082FSW075) occurrences all appear to be located along the same shear-related vein system, although the same vein or shear may not be continuous through all properties.

In 1975, a 6-metre chip sample across the vein at surface near the Ymir-Goodenough boundary assayed 6.2 grams per tonne gold and 36.9 grams per tonne silver, whereas composite grab sampling of the lower dump pile, approximated to contain 90 718 tonnes, yielded 2.6 grams per tonne gold and 12.3 grams per tonne silver (Property File - Junex Resources Ltd. [1975-07-01]: Report on the Ymir Group).

In 1981, underground sampling yielded up to 4.7 grams per tonne gold, 14.4 grams per tonne silver, 0.39 per cent lead and 0.14 per cent zinc over 2.4 metres from the no. 2 level and 2.7 grams per tonne gold, 13.7 grams per tonne silver, 0.07 per cent lead and 0.27 per cent zinc across 3.0 metres on the no. 10 level, whereas a grab sample from the glory hole assayed 17.3 grams per tonne gold, 37.3 grams per tonne silver and 0.53 per cent lead (Property File - Nu-Dawn Resources Inc. [1981-07-31]: Report on YMIR-Protection Property, Nelson Mining Division).

In 1986, underground diamond drilling yielded up to 6.5 grams per tonne gold, 38.05 grams per tonne silver, 1.33 per cent lead and 0.70 per cent zinc over 1.53 metres, from 67.66 to 69.19 metres downhole in DDH Y86-1 and 2.3 grams per tonne gold, 30.1 grams per tonne silver, 0.50 per cent lead and 0.79 per cent zinc over 1.50 metres, 79.15 to 80.65 metres downhole in DDH Y86-2 (Assessment Report 15524). Both drillholes were located east of the main shaft and below the No. 7 level workings.

In 1936, 17 possible mineralized ore blocks were identified totalling 110 486 tonnes averaging $9.84 in gold and silver with gold at $34.00 an ounce and silver at $0.45 an ounce, or approximately 9.8 grams per tonne gold (Property File - Ymir Consolidated Gold Mines Ltd. [1936-03-02]: Vertical Projection Map through Ymir Mine - Showing immediate tonnage available for milling).

In 1984, it was suggested that 86 183 tonnes of ore averaging 9.6 grams per tonne gold remained in the old stopes (Property File - C.T. Exploranda Ltd. [1985-01-10]: News Clippings - Ymir).

Total production from 1895 to 1970 was 327 646 tonnes with an approximate grade of 10 grams per tonne gold and 34 grams per tonne silver. Combined lead and zinc content was approximately 1.7 per cent.

The Ymir, Rockland, and Mugwump claims were staked in July and August 1895 by Joseph and Jerome Petrie and Oliver Blair. The Golden Horn, Robertson and Nora fractions were staked in 1896 by Petrie, Wood and Robertson, and Crown-granted (Lots 1711, 1712 and 2301, respectively) in 1897 and 1898. The Poutney and Lawrence fractions were staked by the operating company in 1897 and Crown-granted (Lots 2302 and 2303) in 1898.

The property was acquired in November 1896 by The London and British Columbia Goldfields Limited. A program of extensive underground development was begun. A mill was built at the 1036-metre elevation, with a 732-metre tramway to the No. 3 adit. In August 1898, a subsidiary company, The Ymir Gold Mines, Limited, was incorporated in London, England, to be the operating company. An 80-stamp mill was put into operation in 1900 and a cyanide plant for treating the tailings was installed in 1901. The No. 10 level crosscut was collared just above the mill and by 1902 it had been driven 657 metres to intersect the vein 305 metres below the outcrop. Development work in the upper levels was done in the No. 2 and 3 adits, and on the No. 4 and 5 levels via a winze from No. 3 adit. The No. 10 level was connected by a raise to the winze from the No. 3 adit. Little ore was found below the seventh level. By 1904, the milling operation was reduced to 40 stamps. Production gradually decreased until the mine closed in 1908. In 1907 and 1908, considerable surface exploration was carried out in search for the source of mineralized float occurring further up the mountain. On the No. 2 level, a crosscut was driven 244 metres into the hill in search of a parallel vein. On the No. 10 level, the vein was drifted on for 335 metres to the east.

Ymir Gold Mines, Limited, a private company incorporated in February 1933 by J.F. Coats and associates of Vancouver to acquire the adjacent Goodenough property (MINFILE 082FSW073), acquired an option on the Ymir mine but no work was reported under this agreement.

Ymir Consolidated Gold Mines, Limited, was incorporated in September 1934 to acquire and operate the Ymir and Goodenough properties. Some high-grade ore was known to occur in the Goodenough, and sampling in the Ymir reportedly indicated large blocks of low-grade ore. On the basis of this, the company installed a 125-ton-per-day mill at the Ymir property in 1935. The Goodenough ore had to be trucked to the mill. The mill operated from July 18 to November 30, 1935, mainly on Goodenough ore. Exploration in the east end of the upper Ymir workings located a small oreshoot and the mill resumed operating in June 1937 at 30 tons per day; milling operations continued into May 1938, when the company ceased operations. Lessees worked the property intermittently from 1937 to 1944, mining from pillars, stope remnants and dumps.

Americonda Mines Limited, incorporated October 1956, held options on the Ymir and Goodenough properties. Only limited work on the Goodenough was reported during 1956. Silver Dawn Mines Ltd. apparently held the Ymir and Goodenough properties in 1970. Some adits were rehabilitated and the workings prospected for scheelite. In 1973, the Ymir property was owned by Murray Zulps and associates, of Vancouver. Some rehabilitation work was reported and a small amount of ore was shipped. Issa Fahel optioned the seven Crown-granted claims of the Ymir group from Zulps and associates in July 1975. This agreement to purchase was assigned to Junex Resources Ltd. in September 1975.

In 1981, Nu-Dawn Resources examined and sampled the area. In 1984, C.T. Exploranda and Arizako Mines completed programs of soil and rock sampling on the area. In 1986, Nu Dawn Resources completed five rotary drill holes, totalling 297.2 metres, and two underground diamond drill holes, totalling 161.2 metres.