The Surprise prospect is at 1400 metres elevation. It straddles Surprise Creek downstream from the mouth of a minor tributary, Dave Morgan Creek. Surprise Creek is a northwest flowing tributary of Ferguson Creek. The Surprise (L.8661) claim is the central tenure in a small, linear, cluster that consists of the Welsh (L.8663), Surprise (L.8661) and Adelina Fr. (L.8662) claims.
The property was located in the late 1890s and explored intermittently through to the mid 1920s. The Surprise vein was exposed at 15.25 metres depth in a crosscut in 1899, and a 3.66 metres wide mineralized zone was explored over a strike distance of 150 metres in 1914. The property was idle after the First World War but exploration resumed in the 1920s, when it was owned by D. Morgan. He did a considerable amount of trenching along the vein. The target was a large tonnage of low-grade silver-lead deposit. The workings were in disrepair in 1929.
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 Surprise area is underlain by folded, deformed and schistose rocks of the Index Formation. They include green, grey to black chloritic and/or carbonaceous metasedimentary schist and intercalated beds of limestone. The latter is locally altered to marble and ranges in colour from white to cream and from grey to black, depending on siderite and carbon content. The limestone is thinly layered and varies in width up to 15.2 metres. Thick units resembling the Badshot and/or Lade limestone occur in parallel bands that may well be fold repetitions. There are five major bands of limestone in the Galena Creek area (to the north of Surprise Creek). In the early 1900s, they were known to prospectors as the Black Warrior, Silver Leaf, Ellsmere Ledge, Horne Ledge and Surprise Limestones.
The Surprise claims are underlain by chlorite schist interbedded with an 18 metres wide body of limestone. The rocks strike at 150 degrees and dip at 75 degrees to the northeast. They are cut by joints that have a 030 strike and 80 degree dip to the southeast. They are also cut by a fissure vein that strikes to the east and dips at 80 degrees to the north. This vein has regular, sharp, walls where it cuts limestone and schistose slate. It is oxidized on surface and has an iron-rich, cap that contains a small amount of gold. At depth, it contains pyrite and galena in a gangue, that is calcareous and contains numerous inclusions of chlorite schist. The vein included a 0.25 metre wide lens of solid galena and approximately 1.0 metre of "concentrating ore". In 1914, an "average" sample across 3.66 metres was reported to contain a trace gold, 96 grams per tonne silver and 9.6 percent lead.
By 1924, the orientation of the vein had either been reinterpreted, or work was by then focused on a second, concordant, "vein" or replacement deposit, located between steeply tilted greenish schists and a hanging wall limestone band. This structure was described as being "persistent" and traceable for 300 metres along a strike of 158 degrees and dip of 80 degrees to the northeast. The replacement zone is between 2.4 and 3.0 metres wide and contains pyrite and galena. A sample across 1.52 metres assayed a trace gold, 27.43 grams per tonne silver and 11.4 per cent lead. Lower down the creek, "where a tunnel has been driven across the vein" the mineralization is exposed in a narrow band, and a sample across 0.53 metre assayed a trace gold, 72 grams per tonne silver and 16.3 per cent lead. There is very little zinc in the system. The northwest workings were in disrepair in 1929, but Gunning (GSC MEM 161) shows that they are all within 3.1 metres of the southwest contact of the limestone. He notes that dump material is composed of limestone with abundant ankerite, magnetite, pyrite galena and some sphalerite. There is only a small amount of quartz.
During 2006 through 2009, Mineral Mountain Resources Ltd. completed programs of prospecting, geochemical (soil, silt, talus fines and rock) sampling and an airborne geophysical survey on the area as the Kootenay Arc property.
