The Ajax is 2.0 kilometres north of Lardeau Creek and 1.0 kilometre east of Ferguson Creek. It is at approximately 1625 metres elevation on a spur on the southwest slope of Nettie L. Mountain. The Ajax workings are part of the past producing Nettie L. [082KNW100] mining operation.

The Nettie L. area is covered by a well-defined cluster of crown granted mineral claims. The principal tenures are the Nettie L. (L.4954), Nettie L. Fraction (L.5689), Ajax (L.4955), Copper Reef (L.4957), Lulu Bell Fraction (L.4958) and Good Luck (L.4956). The main workings are on the Nettie L. (L.4954) claim. However, the "main lead" extends to the southeast, where adits driven on the Copper Reef property exploit the vein on the Ajax claim. The two sets of workings are approximately 400 metres apart. The vein structure also extends to the northwest of Nettie L., where it was accessed by means of an adit on the Gyp Fraction (L.5691) [082KNW010].

The Ajax, Nettie L. and Gyp Fraction claims were located in 1892 by Mr. W.B. Pool, who went on to form Great Western Mines Limited, in 1901, to develop them. The Ajax claim was stripped and trenched in 1899, and approximately 90 metres of underground development was completed in 1901. Great Western Mines Limited acquired the Nettie L. and adjacent tenures in 1901 and, the following year, acquired the Silver Cup [082KNW027] mine to the south of Lardeau Creek - with the intension of putting both operations under the same management. In 1902, the company installed an air compressor and a 60-horse power boiler on the Nettie L. property and operated the mine until the higher-grade ores ran out, in 1903. It then built a 90 tonne per day mill and concentrator at Five-mile, on Lardeau Creek, and erected a tramway to the Nettie L. The mill was designed to treat lower-grade ore from both the Nettie L. and Silver Cup operations; however, it failed to do so and the Nettie L. mine shut down in 1904. The Nettie L. and Silver Cup operations were acquired by Ferguson Mines Limited in 1909. The company reopened some of the old workings, and drove three crosscuts and developed four levels on the Ajax claim. An additional 30 metres of development work was completed the following year. Daney and Company leased the Nettie L. and Ajax in 1912 and made small shipments from the workings in 1912, 1913 and 1914. In 1929, the Ajax workings were in a state of disrepair. However, the following year, Gold Prospects Limited acquired an interest in the operation. In 1936, Security and Investment Corporation Limited made repairs to the road and buildings. Similarly, a decade later, Cansil Consolidated Mines Limited optioned the property, reopened the adits and made some necessary repairs to the infrastructure. It also installed a compressor and did some diamond drilling.

In 1950, Trout Lake Mining Company was formed to develop the Nettie L. [082KNW100], Ajax [082KNW099] and Gyp [082KNW010] deposits. At the time, there were reported to be five adits on the Ajax claim, although only three were then accessible. The company rehabilitated the old workings, once again, and drove a new adit into the nose of the ridge, at 1556 metres elevation. The four old adits, (Nos. 2, 3, 4 and 5) were driven into the Ajax from the Copper Reef claim on the Ferguson Creek slope, between 1604 and 1553 metres elevation. Adits No. 2 and 3 are 11.6 metres apart vertically and are connected through two sublevels. The No. 3 level is also linked to an inclined shaft. There is a third sublevel that has been developed above the No. 2 level and there are open-cuts at 1630 metres elevation. In the 1950s, the Nettie L. had over 2100 metres of workings on four levels over a short, 100 metres difference in elevation.

The Trout Lake area is underlain by a thick succession of sedimentary and volcanic rocks of the Badshot Formation and Lardeau Group near the northern end of the Kootenay arc, an arcuate, north to northwest trending belt of Paleozoic and Mesozoic strata that is now classified as a distinct, pericratonic, terrane. The arc rocks are bordered by Precambrian quartzite in the east and they young to the west, where they are bounded by Jurassic-age intrusive complexes. They were deformed during the Antler orogeny in Devonian-Mississippian time and were refolded and faulted during the Columbian orogeny, in the Middle Jurassic. A large panel, the "Selkirk allochthon", was later offset to the northeast by dip-slip motion along the Columbia River Fault.

The Badshot formation is composed of a thick Cambrian limestone that is a distinctive marker horizon in the Trout Lake area. It is underlain by Hamill Group quartzite and it is overlain by a younger assemblage of limestone, calcareous, graphitic and siliceous argillite and siltstone, sandstone, quartzite and conglomerate, and also mafic volcanic flows, tuffs and breccias, all of which belong to the Lardeau Group. The rocks are isoclinally folded and intensely deformed, but only weakly metamorphosed. They occur as intercalated beds of marble, quartzite and grey, green and black phyllite and schist. Fyles and Eastwood (EMPR BULL 45) subdivided the group into six formations (Index, Triune, Ajax, Sharon Creek, Jowett and Broadview) of which the lowermost (Index) and uppermost (Broadview) are the most widespread. The Triune (siliceous argillite), Ajax (quartzite) and Sharon Creek (siliceous argillite) are restricted to the Trout Lake area. The Jowett is a mafic volcanic unit.

The Nettie L. Ajax, Gyp and other tenures on Nettie L. Mountain cover a northwest trending "ledge", approximately 18 metres wide, that contains quartz-carbonate veins that carry pyrite, galena, sphalerite and chalcopyrite, and values in gold and silver. The surface trace is commonly marked by an oxidized "iron cap" that is readily visible in areas of thin cover. The area is underlain by siliceous argillites of the Triune and Sharon Creek Formations, by quartzite of the Ajax Formation and by grits and black phyllites of the lower part of the Broadview Formation. The rocks are folded, deformed and locally highly schistose. The main area of mineralization, encompassing the Gyp, Nettie L. and Ajax mine property, is bounded on the northeast by the Cup Creek fault, on the southwest by the (probably faulted) base of the Broadview formation, and on the southeast by the Brow Fault. It is 1000 metres long and 200 to 250 metres wide, and covers a portion of the core of the Silver Cup anticline. This is a regionally important isoclinal fold that is over-turned to the southwest and plunges at 25 degrees to the northwest. It imparts an axial plane cleavage that strikes to the northwest and dips at 60 degrees to the northeast. The rocks are cut by axial plane shears and northeast trending cross faults. One of the latter displaces the anticline between the Nettie L. and Ajax workings. The ore lenses are controlled by faults and drag folds in the core of the fold structure. In the Nettie L. [082KNW100] mine, they are also found in cross faults. The structure is complicated by locally large displacements on post-mineral faults in the plane of the "main lead".

In the Ajax workings, the northwest trending fault that controls the "main lead" at Nettie L. is barren. However, mineralization is found along smaller shears or fractures, between 18 and 61 metres into its hanging wall. The veins are parallel to the fault. They dip about 45 degrees to the southwest near surface, but turn back to a steep northeast dip at shallow depth. They are gash-type veins in highly broken and contorted strata. The ore zones ranged from 0.15 to 3.0 metres in width. The main lens in the Ajax was located on a sublevel 15.24 metres above the No. 3 level. At this locality, the vein contained enough sphalerite, galena and chalcopyrite to warrant the development of a small stope. The lens appears to plunge to the north, although it was not found on the No. 3 level. It may; however, have breached surface as there is a caved open cut with a fairly large dump on its inferred projection. The zone appears to have consisted of quartz, carbonate and phyllite. At the south end of the sublevel, a sample across 1.07 metres assayed 2.74 grams per tonne gold, 92.6 grams per tonne silver, 1.33 per cent copper, 2.99 per cent lead and 8.3 per cent zinc. A considerable amount of work was done to explore lower levels but no other ore zones were encountered. However, a few showings were located in the hanging wall of the main fault in the No. 4 adit. The mineralization in the Ajax mine is similar to that of the Nettie L., however the veins may contain more carbonate and sphalerite. An occurrence of earthy wad was found in the upper workings of the Ajax mine. An impure sample assayed 9.36 per cent manganese.