The Truman (Trillium) occurrence immediately southeast of Lost Creek near its junction with Lime Creek and at an elevation of approximately 700 metres.

Regionally, the area is underlain by quartz arenite sedimentary rocks of the Neoproterozoic to Lower Cambrian Hamill Group, undivided sedimentary rocks of the Cambrian Laib Formation and fine clastic sedimentary rocks of the Ordovician Active Formation. The rocks are folded into a series of generally north-trending anticlines and synclines. To the east and west these have been intruded by granodioritic rocks of the Cretaceous Anstey pluton, and to the north and south small bodies of syenitic to monzonitic intrusive rocks are exposed.

Locally, a large anticlinal structure is exposed within Lower Cambrian Laib Formation and Lower Cambrian Reno Formation stratigraphy along the west flank of Truman Hill. The Reeves member (Laib Formation) limestones are exposed on the east limb, near the Mona adit, and on the west limb near the base of the hill near the Trillium adit. To the east, the anticlinal stratigraphy is in fault contact with argillites of the Ordovician Active Formation. Reeves limestones are underlain by phyllites, argillites and quartzites of the Truman member (Laib Formation) and the core of the anticline contains micaceous quartzites of the Reno Formation overlying white and brown, more massive, quartzites of the Navada member of the Lower Cambrian Quartzite Range Formation.

Mineralization appears confined to dolomitized limestone at the base of the Reeves Formation and consists of pyrite, pyrrhotite, sphalerite, and galena, both disseminated and in masses within 60- to 100-centimetre thick dolomite bands interlayered with barren limestone. The deposit description, along with the high amount of silver, indicates a manto-type deposit.

At the Trillium adit, the sulphides (galena and sphalerite) are coarser-grained and more massive than at the Mona adit and are associated with a 1.0-metre wide shear zone at the contact between whitish dolomite of the Reeves Formation and siliceous argillite of the Truman member. The sediments have been folded into a tight syncline fold with an axis of 0 degrees and a plunge of approximately 30 degrees south.

In 1995, a rock sample (B51891) assayed 9.63 per cent zinc, 2.32 per cent lead, 0.07 per cent cadmium and approximately 68.4 grams per tonne silver over a few centimetres (Assessment Report 23955).

At the Truman (Truman Hill) zone, trenches located near the top of the hill on the Truman No. 3 claim and approximately 470 metres east of the Trillium adit expose a 0.6- to 1-metre wide zone of galena-sphalerite mineralization. The mineralized zone strikes north 30 degrees east and dips 30 degrees to the west in a dolomite and/or white limestone host and is associated with a northwest-striking shear zone with a 30-degree southwest dip. The mineralized zone has been traced along strike for at least 250 metres. The Mona adit is located near the top of the hill on its southeast side.

A drillhole (V3) from the southern end of the mineralized zone is reported to have yielded 10 per cent zinc over 0.6 metre (Assessment Report 20498).

In 1995, a grab sample (B51893) from a southern trench assayed 9.70 per cent zinc, 0.52 per cent lead, 0.14 per cent cadmium and 15.7 grams per tonne silver, whereas a sample (B51895) form the northern trench assayed 0.315 per cent lead and 4.745 per cent zinc (Assessment Report 23955).

In 1996, rock samples (TR-1 to TR-7) yielded from trace to 2.56 per cent lead, 4.06 to greater than 10 per cent zinc, trace to 0.15 per cent cadmium and trace to 59.1 grams per tonne silver (Assessment Report 24910).

Other zones of similar mineralization are reported at the Truman drift, located approximately 700 metres north of the Trillium adit on the northwest side Lost Creek and northeast of Lime Creek at an elevation of 868 metres. A third adit or drift is located along Lime Creek at an elevation of approximately 830 metres.

In 1959, a 20-centimetre chip sample across the best mineralization assayed 137.2 grams per tonne silver, 7.41 per cent lead and 17.1 per cent zinc (Bulletin 41, page 152).

In 1984, three samples from muck piles in the Truman drift assayed 3.4 grams per tonne silver (Assessment Report 12152).

The area has been historically explored in conjunction with the nearby Emerald Tungsten (MINFILE 082FSW010) and Jersey (MINFILE FSW009) mines.

In 1911, the Trillion tunnel/adit was developed by L.R. Clubine. In 1927, The Consolidated Mining and Smelting Company of Canada Ltd. optioned the area as the Mona property and completed four diamond drill holes, totalling 621.9 metres, before the option was dropped. The Mona adit was likely developed at this time.

In 1946, L.R. Clubine re-staked the area as the Truman group of claims. In 1947, Valley Mining Co., a subsidiary of New Jersey Zinc Co., optioned the claims and completed a program of geological mapping and three drillholes, totalling 187.2 metres. In 1949, Conwest Exploration Co. Ltd. optioned the claims. In 1950, the claims were optioned and later purchased by American Zinc Co. In 1954, American Zinc Co. completed 17 drillholes, totalling 2367.6 metres.

In 1979, Mentor Exploration and Development Co. optioned the Truman property and conducted programs of prospecting and sampling on the area through 1984. In 1990, the area was soil sampled as the Truman 1-3 claims. In 1994, a program of prospecting and geochemical sampling was completed on the area as the Lost Gold property. During 1994 through 1996, Sultan Minerals Inc. conducted programs of geochemical sampling, geological mapping and a 510 line-kilometre airborne geophysical survey on the area as the Blue Jay 1-6 claims.