The Lake No. 1 sodium carbonate deposit occupies a small, sharp depression near a faulted contact between syenite of the Cherry Creek unit of the Late Triassic-Early Jurassic Iron Mask batholith to the north and Eocene Kamloops Group mafic porphyritic volcanic rocks to the south. The salt deposit underlies a small alkali lake, Salsola Pond. Its drainage basin is about 182 hectares in extent, of which about three-quarters is underlain by porphyritic volcanic rocks. Another alkali lake containing sodium sulphate crystal, (Cedars, 092INE076), lies 1500 metres east. Salsola Pond was nearly dry when examined in October, 1937. The surface was covered by a heavy encrustation of dried soda (natrite), underlain by 0.6 to 1.2 metres of soft black mud, beneath which a solid crystal bed occurred. In September, 1938, a thin layer of brine covered nearly half the lake. The area of the bed is between 1.2 and 1.6 hectares, and that about 1.2 hectares are underlain by permanent crystal. The Minister of Mines Annual Report 1930 states that holes drilled with a steam jet intersected from 5.4 to 10.9 metres of solid crystal, without, in places, bottom being reached. If these figures are assumed as correct, the lake would contain approximately 90,710 tonnes of permanent crystals, or roughly 27,213 tonnes of sodium carbonate and sulphate (Bulletin 4). In 1930, the typical analysis was given as: 63 per cent H2O; 1-5 per cent insolubles; 22-26 per cent salts; Composition of salts: 92 per cent Na2CO3; 8 per cent Na2SO4.
It is understood from the owner that analyses vary in respect to the proportion of sodium carbonate and sodium sulphate (mirabilite) in different parts of the bed. In 1938, samples were taken from the surface crust and settling tank and assayed as follows: Surface Crust: 57.9 per cent Na2CO3; 39.8 per cent Na2SO4; 1.1 per cent insolubles. Recrystallized material from settling tank: 58.9 per cent Na2CO3; 40.6 per cent Na2SO4. From these results it appears probable that the proportion of sodium sulphate in the quoted analysis from 1930 is too low to be truly representative.
The deposit was worked by the B.C. Sodium Syndicate from 1933 to 1935 and about 907 tonnes of impure natron or sal soda was shipped to Royal Crown Soaps, Limited, in Vancouver and Calgary. The method of recovery was to liquify the crystal by means of steam, pump the solution to a settling tank to remove insoluble impurities, and recover the sodium carbonate and sodium sulphate by recrystallization.