The McLean occurrence was first staked as the Evelyn group at the turn of the century. Some exploration work occurred from 1902 to 1905, possibly trenching and the development of small adits.

In 1915, the property was reported on in the Minister of Mines Annual Report. It was stated that a vein filling a small fissure occcurred in quartzite and greyish limestone, striking southeast with a southwest dip of 70 degrees. Several opencuts had been made along the vein, and along other veins not on the strike of this vein. A 7.6-metre adit showed the vein to be 20 to 38 centimetres wide

A 7.6-metre tunnel on the face of a very steep cliff shows the vein to be from 8 to 15 inches wide, largely consisting of iron oxide and sulphide and talcy material, but also containing streaks and nodules of galena. A sample across 25 centimetres of rusty material, which was considered as containing lead carbonate yielded only 212.57 grams per tonne silver and 2 per cent lead. A sample of clean galena however, assayed 1.37 grams per tonne gold, 3915.46 grams per tonne silver and 63.6 per cent lead (Minister of Mines Annual Report 1915, page 99).

The property was idle until 1956 when W.C. Wolfenden acquired it by staking. Some of the older workings were cleaned out and a small amount of work was done by optionees over the next several years.

In 1971, Purcell Development Co. Ltd. held the property as the Evelyn claims, conducting a mapping and soil sampling program. During 1972 some surface sampling was done by Purcell Development and in 1973 the company completed 6 diamond-drill holes totalling 457 metres. The company also examined over 168 metres of old surface trenches cut into gossanous exposures.

In 1973, a mix of sulphides was reported in veins, mainly galena, that varied from 45 to 90 centimetres in width. The veins strike 125 degrees and dip between 55 and 65 degrees to the southwest. Assays of material from these trenches included 0.91 metres of mineralized gossan that yielded 428.58 grams per tonne silver and 5.5 per cent lead (Assessment Report 5073). The veins appear to be continuous over 168 to 183 metres

The area of the occurrence is underlain by rocks of the Middle Proterozoic Mount Nelson Formation, Purcell Supergroup.