The Princeton-Tulameen Coal mine is situated on the north side of the Tulameen River, west of Asp (China) Creek, on the northern outskirts of the town of Princeton.

This mine occurs at the centre of the Princeton Basin, a northerly-trending half-graben superimposed on volcanics and sediments of the Upper Triassic Nicola Group. The basin is separated into a northern and southern area by the gentle, northwest striking Rainbow Lake anticline. The southern area, in which this deposit occurs, is a structural depression with beds dipping 10 to 20 degrees south near Princeton, and gently east between Asp Creek and the Tulameen River. South of Princeton are two major east striking asymmetric anticlines with gentle to moderate southerly dips continuing to the south. On the western margin of the basin the strata dips approximately 50 degrees east. In the southern part of the basin, two north to northwest plunging anticlines are present. The basin is bounded and cut in places by a number of approximately north to northeast-striking, westerly dipping faults. The main faults are the Asp Creek fault and the Boundary fault.

The Princeton-Tulameen coal deposit is hosted in a sequence of sandstone, shale, waterlain rhyolite tephra (tuff) and coal, up to 2000 metres thick, comprising the Eocene Allenby Formation (Princeton Group). The mine is developed in the Princeton-Black-Blue Flame coal zone, the stratigraphically lowest and thickest of four significant coal-bearing zones in a 530-metre section in the Allenby Formation. Its thickness varies from 1.6 to 19.2 metres with approximately 9.1 metres of coal. The coal occurs in bands 7 centimetres to 5.5 metres thick with interbeds of shaly coal, bentonite, sandstone and shale separating the individual seams. The partings and beds associated with the coal change thickness and stratigraphic position laterally, making correlation difficult. Coal quality also varies laterally. The Princeton-Black-Blue Flame coal zone was also mined at the Princeton Colliery (092HSE089), Tulameen Collieries (092HSE210), the Pleasant Valley Nos. 2 and 4 mines (092HSE211), the Black mine (092HSE212) and the Blue Flame Colliery (092HSE216).

The coal seam at this mine strikes approximately 070 degrees and dips 16 to 20 degrees southeast. Underground workings have traced the seam downdip for 550 metres and along strike for 900 metres. The deposit is 2.1 to 3.2 metres thick. A representative seam section measured in the lower workings of the mine contained 2.91 metres of coal with five thin clay partings, three of which were 6 millimetres thick, and two of which were 13 millimetres thick (Minister of Mines Annual Report 1944, page 122).

The coal is non-coking in character and ranges in rank from sub-bituminous B to sub-bituminous A. A sample of mine-run coal analyzed as follows (in per cent) (Bulletin 14, page 19):

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Moisture 14.9

Volatile matter 29.5

Fixed carbon 47.6

Ash 8.0

Sulphur 0.2

Calorific value 9810

(B.T.U.'s per pound)

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Four additional samples analysed 12.1 to 16.2 per cent moisture, 25.2 to 31.3 per cent volatile matter, 41.7 to 48.8 per cent fixed carbon, 5.0 to 22.8 per cent ash, 0.30 to 0.41 per cent sulphur and 7780 to 10360 British Thermal Units per pound (Bulletin 41, page 19).

Coal was initially mined by Oscar Lind in 1935. The deposit was subsequently operated by Tulameen Valley Coal Company (1936) and Princeton-Tulameen Coal Company (1937-1944). The mine was abandoned in 1944 due to squeezing of the lower underground workings. A total of 175,189 tonnes of coal was mined.