The Mika claims are situated 8 kilometres northeast of Clinton on the Mond Ranch. The showings occur on the west bank of the Bonaparte River, just south of its confluence with Fiftyseven Creek.
The hostrock for the chromite prospect is eastern facies serpentinite of the Cache Creek terrane (Carboniferous to Triassic Cache Creek Complex). This consists of a Late Triassic accretionary prism/subduction complex associated with the Nicola volcanic arc. The melange contains Pennsylvanian and Early Permian limestones, chert, basalt, argillite and ultramafic rocks in a matrix of Permo-Jurassic chert and argillite. Locally, Tertiary flood basalts form hill cappings. A thick mantle of till and alluvium covers the area.
The property is underlain by shales and carbonate rocks with interbedded basic and ultrabasic intrusives. The intrusives trend north to northwest and are concordant with the volcanic sedimentary series to the west. The basic intrusives consist of slightly altered and medium-grained diorite, while the ultrabasics consist of serpentinized peridotite, dunite and pyroxenite, which in some places have been completely altered to serpentine.
The claim area contains two zones of ultrabasic rock containing minor quantities of asbestos fibre. The zones lie approximately 900 metres apart and run parallel to one another. The western ultrabasic zone strikes north-south, dips 40 to 65 degrees west and has a maximum observed width of 39.6 metres. The irregular and discontinuous zone is intermixed with diorite and contains two serpentine bodies. The eastern ultrabasic zone, which has been observed over a width of approximately 366 metres, consists of a complex assemblage of conglomerate-associated serpentine bodies alternating with chert. The westernmost serpentine body consists of relatively fresh peridotite with negligible amounts of fibre.
A large serpentinite body with dunitic and harzburgitic zones has been mapped on the property (Assessment Report 8111). The serpentinite is massive, sheared and locally quite friable. Late, thin chrysotile veinlets, up to 2 millimetres wide, locally web the serpentinite. Talc is locally intensely developed. Dunite and harzburgite zones have been identified but these are of nominal areal extent. Where exposed, serpentinite is in contact with metasediments and the contact trends 160 to 165 degrees with an undetermined dip. Regional mapping information indicates that serpentinite outcrops northwest and southeast of the claims. Within the area there is a conglomerate, with 1 to 20-centimetre clasts of harzburgite, dunite and serpentinite in a calcareous matrix. It has been suggested by Wilson (Assessment Report 8111) that this represents a late, covering conglomerate that remains as small relict patches.
Chromite mineralization is restricted to the dunitic phase of the serpentinite. Chromite occurs as disseminations, small pods and lenses. Stevenson (1941) identified two chromite pods 1.5 to 2 square metres in area. A sample of the chromitite yielded (in per cent; Bulletin, unpublished, 1941):
------------------- Cr2O3 52.8 Al2O3 12.1 CaO 0.2 MgO 13.2 MnO 0.17 TiO2 1.44 SiO2 3.48 NiO 0.12 FeO 13.9 ------------------- |
The old workings are mostly caved, including the adit and shaft, and little chromite is seen in outcrop. Platinum and gold geochemical surveys have provided poor results, although this may be due to the amount of cover material (Assessment Reports 8111, 8677, 14977). A 1979 sample from the collar of the old shaft assayed 38.73 per cent chromium (Assessment Report 8111).
In 1932, W.N.D. McKay staked the Winnifred claims over the area and completed minor trenching and underground testing of chromite occurrences. By the time geologist J.S. Stevenson examined the property in 1938, an adit had been advanced to 7.3 metres length with a 7.3-metre-deep shaft and three short levels, and the surface trenches had sloughed in. By 1979, the underground workings had caved.
The first asbestos claims were staked in 1952 by Gordon Blaney, Adam Derry and Vic Bjorkman. Western Asbestos later optioned the claims but dropped the option shortly after without completing any work. The property sat dormant until 1957, when the Venus and Mac claims were staked over the area. New Jersey Zinc Exploration Company Limited optioned the property and conducted geological mapping, magnetometer geophysical surveying and a modest program of follow-up trenching. The option was then dropped the following year. Between 1958 and 1959, the property owners completed bulldozer trenching to test the extent of the asbestos mineralization.
The property again sat dormant until 1967, when Adam Derry staked the Jo claims on behalf of Riviera Mines Limited. That year, exploration consisted of geological mapping and geophysical surveying.
The ground then lay dormant until 1979, when CCH Resources Limited (later Campbell Resources Incorporated) staked the Mika claims over the area and conducted geological and geochemical surveying on the Mika claim. Additional mapping and sampling was completed the following year. Seven chromite showings with greater than 32 per cent and up to 42.4 per cent chromium (III) oxide were identified. Afterward, the Mika 2 to 4 claims were dropped.
By 1986, the Mika claim was owned by Mascot Gold Mines Limited. A geochemical evaluation was undertaken to determine if precious metals were associated with the known chromite showings. Minor platinum was found to be associated with a poorly exposed chromite zone. Later that same year, the Mika claim was sold to Corona Corporation.
Tilava Mining Corporation acquired the former Mika claim area as part of the Aw property in 2000. That year, exploration consisted of ground geophysical surveying over an area of serpentinized peridotite on the eastern side of the Bonaparte River. The main exploration targets for the property were chromite and magnesium, though sporadic work including small hand-excavated trenches and pits was carried out on known bentonite showings.
In 2008, Tilava Mining Corporation excavated eight pits to test the layer of leonardite overlying the valley floor. Excavation exposed a layer of bentonite overlain by leonardite. In 2011, Tilava mechanically stripped a layer of overburden to expose the bentonite layer. Three of the previously excavated trenches and pits were enlarged and deepened, and two new small pits were excavated and sampled.
The following year, Tilava collected rock grab samples of bentonite from excavated trenches or stripped areas. In August of 2012, Tilava received permits allowing them to considerably enlarge the size of the existing bentonite mine and extract 10,000 tonnes of bentonite for bulk sampling.
