The property lies on the northwest flank of Frenchman Cap Dome in a complexly and isoclinally folded metasedimentary sequence. The core gneisses of the dome lie beneath gently north-dipping metasedi- mentary rocks, which grade upward into overlying metasediments consisting of micaceous schist, calc-silicate schist and gneiss with intercalated layers of marble. Pegmatite and associated medium- grained granitic rocks replace and impregnate the metasediments. The metasediments are tentatively correlative with the Hadrynian Windermere Group.
Three mineralized areas, referred to as the E, F, G and M zone (MINFILE 082M 084), the Creek and T zone (MINFILE 082M 083) and the Q, R, V and U zone, occur as contorted layers and lenses several metres thick and are traced intermittently over a strike length of several kilometres within schist, siliceous calc-silicate gneiss, quartzite and marble. The principal sulphides are sphalerite, pyrrhotite, galena, pyrite and minor chalcopyrite, locally associated with barite and fluorite. Very fine grained sphalerite and pyrrhotite with minor galena and rounded quartz eyes are common. Equally common are layers containing medium-grained dark-brown sphalerite with interstitial quartz and scattered quartz augen. Galena and sphalerite also occur as scattered grains in marble, calcareous quartzite and fluorite.
In the sulphide layer, lenses of massive sulphides up to 1.5 metres thick are common. They are complexly folded within themselves on axes that plunge to the west parallel to the folds in the surrounding rocks. The folds in the sulphides, which are outlined by banding and by discontinuous layers of schist, gneiss and quartzite, are irregular in form and usually disharmonic.
The Q, R and V zones, which lie 4 kilometres west of the main E zone (MINFILE 082M 084), form a near continuous sulphide layer, outcropping for almost 1 kilometre, on the limb of a phase 1 syncline. The U zone lies 1 kilometre along the strike to the east.
A major phase 2 recumbent fold, closing to the south, is referred to as the U-V synform. Its axial plane strikes 5 degrees and dips 25 degrees to the west.
Exploration on the Ruddock Creek property dates from the discovery of massive sulphide mineralization and the subsequent staking of the ground in 1960 by Falconbridge. Falconbridge conducted the most extensive exploration over the period 1961 to 1963. Core drilling was completed at the E zone (MINFILE 082M 084) and the G, M, T, Q, U and V showings. Cominco Ltd. optioned the property from Falconbridge in 1975, carrying out drilling and geophysics on the property.
Doublestar Resources Ltd. acquired Falconbridge’s 58.9 per cent interest in January 2000 and in August and September 2000 carried out a detailed mapping program on the property.
In February 2001, Doublestar Resources Ltd. purchased the 41.1 per cent interest of Cominco Ltd. to hold a 100 per cent interest in the property.
In March 2004, Cross Lake acquired an option on the property from Doublestar Resources Ltd. Cross Lake drilled 11 holes totaling 1839 metres in 2004, expanding the E zone (MINFILE 082M 084) to the west and north.
In early 2012, Imperial Metals Corp. released an updated NI 43-101–compliant inferred and indicated resource estimate (see MINFILE 082M 084).
In 2012, Imperial Metals Corp. completed an exploration program which included surface diamond drilling on the V and Creek (MINFILE 082M 083) zones, underground diamond drilling on the lower E zone (MINFILE 082M 084), and an additional 69 metres of underground development for the collection of a metallurgical bulk sample. In total, 18 holes were completed in the V zone, seven holes in the Creek zone (MINFILE 082M 083) and 26 holes from underground, for a total of 10 081 metres of surface drilling and 5843 metres of underground drilling. The highlight of the V zone drilling was drillhole RD-12-V40, which showed a zinc content of 24.04 per cent and lead content of 5.15 per cent over 6.4 metres (4.6 metres true thickness).