The Keystone occurrence is located just south of the confluence of Boulder and Thibert creeks, about 8 kilometres west of the north end of Dease Lake.
In 1931, stripping and open-cutting the old Keystone showing exposed "a zone of quartz stringers in quartz porphyry", located on Thibert Creek below Berry Creek. The owner reported gold values up to $5.50/ton across a width of 12 metres (Minister of Mines Annual Report 1931, page A53). The showing has not been located during recent exploration and is believed to be covered by placer tailings in the area immediately east of the confluence of Berry and Thibert creeks (Assessment Report 17706, pages 8,9).
A drillhole was collared just south of the confluence of Boulder and Thibert creeks (a short distance from the Berry Creek confluence) to test serpentinite, quartz veins and a veined black shale unit where sampling from a backhoe pit yielded up to 0.6 gram per tonne gold (Assessment Report 17706). In the vicinity, there are zones of strong folding, shearing and extensive quartz veining (from stringers to several metres wide) where competent rock units (altered, silicified ultramafic rocks and cherty metasediments) have been dismembered by folding and occur as folded blocks within sheared black shale and serpentinite masses. Deformation seems much less intense away from these zones. The metasediments are part of the Mississippian-Triassic Kedahda Formation (Cache Creek Complex); the Upper Mississippian-Permian ultramafic rocks are also part of the Cache Creek Complex.
Drillhole DDH87-B-3 intersected strongly sheared serpentinite, shale, chert, altered ultramafic and some quartz veining. A 1.5 metre section of drill core analysed 1 gram per tonne gold. Platinum values of up to 0.29 gram per tonne occur in parts of the serpentinite unit in the top-half of the hole (Assessment Report 17706, page 10).
Nu-Lite Industries Ltd. drilled four holes in 1997. Two holes confirmed previous results of 8.57 grams per tonne gold over 7.6 metres (Northern Miner, May 4, 1998).
The Keystone group of 8 claims was owned in the early 1930s by Homer Reklin, of Porter Landing. Open-cutting and stripping was reported in 1931 and some further work in 1933. In 1983, Noranda Exploration carried out reconnaissance exploration over the Thibert Creek area. In 1987, Equity Silver Mines optioned the property from Ed Asp, the owner of the claims and completed a compilation of the data in the area. As a result of the compilation the company did a limited amount of backhoe and hand trenching in the Boulder Creek/Berry Creek area in order to locate the Keystone showing reported in 1931. They were unsuccessful in finding the showing and drilled one, 152 metre diamond-drill hole near the junction of Boulder and Thibert creeks. In 1996, Nu-Lite Industries Ltd. established 8 kilometres of cut line and 14 kilometres of flagged line and conducted a ground magnetometer and VLF-EM survey. In 1998, Nu-Lite Industries completed four diamond-drill holes totalling 648 metres. The drilling was oriented to intersect the downdip extension of the Keystone showing as well as test a mineralized intersection in a hole drilled by Equity Silver Mines in 1987. In 1999, Nu-Lite Industries completed a geological mapping survey over the property. In 2000, Netseers Internet Corp. attempted to find the source of the Thibert Creek placers and possibly the Keystone showing. The company completed detailed mapping and sampling of the placer workings at Delure Creek (104J 055), Five Mile Gulch, Boulder Creek (104J 054) and Berry Creek (104J 007) with the attempt to locate possible sources of gold mineralization within the workings. A total of 90 soil samples were taken in a total of eleven lines which were intended to bracket the areas of the workings and locate possible sources of mineralization. In 2006, Jet Gold Corporation spent two weeks on the ground trying to locate the Keystone showing but were unsuccessful.
In 2015 and 2016, Joseph Hidber collected 7 rock and 19 soil samples on his Thibert Creek mineral claims. A grab sample (sample 158) located at 429329 east, 6520545 north, about 500 metres east of Keystone assayed 0.18 per cent nickel (Assessment Report 36794). The sample is described as and oxidized ultramafic rock with a very light rusty orange surface coating. Some quartz-carbonate veining was observed, and the sample was very quartz rich. Quartz is locally chalcedonic to almost opaline and occurs in 2-millimetre veinlets. The anomalous nickel is related to the samples showing the distinctive green mineral, referred to as fuchsite or mariposite. Several other nickel bearing samples were collected downstream from the Keystone.
