The concession is located approximately 90km North-Northwest of Accra in the Birim Central Municipal Assembly, Eastern Region, Ghana. The general locality has a tropical climate with two seasons of rain, one from June to August and a second from October to November. The area is gently undulating with extensive flat areas. The lease covers part of the Birim River drainage.
The concession is to the South of the towns of Kade and Akwatia, a hub of alluvial Diamond mining activity. The area is situated within the geological field sheet No 57 and 58 in Birim Central Municipal Assembly of the Eastern Region. The concession lies between longitudes 0°43’24’’W and 0°50’30’’W and latitudes 5°25’50’’N and 5°55’00’’N.
The towns of Oda and Asamankese are the major centres in the locality of the licence area. They are serviced with electricity, hospital and telecommunications. The concession area has a gently undulating topography, incised by streams draining into the Birim River catchment. Vegetation is dominated by secondary forest re-growth.
Elevations range from 134m (above mean sea level) along the Birim River to 350m in the Southeast of the concession area. The topography is shallow and essentially controlled by surficial deposits of unconsolidated sediments. Access is good via sealed road from Accra through Asamankese and thereafter by sealed or graded all weather roads to the small towns in the concession area.
The Osenase concession is currently awaiting Ministerial approval.
|1995 to 1996||Cornucopia Resources Ghana Ltd. undertook airborne fixed-wing magnetic, VLF and radiometric reconnaissance ground magnetometer survey lines in the central part of the licence.|
|1996 to 1997||Landsat image interpretation of geology, linear and circular features. Bulk stream sediment sampling with "clusters" of pits excavated at each site to ~2m depth, 41 "Bulk Samples" collected of alluvial material.|
|1996 to 1997||321 test pits dug to bedrock for 221 samples totalling 110m3. 2m deep auger holes drilled in the base of 304 pits. 1,275 diamonds from 32 dispersion haloes/bulk sample sites and 33 concentrate samples were sent for detailed morphological.|
Systematic exploration by Cornucopia showed massive meta-ultramafic occurs in several horizons from which GCD have already produced diamonds. Diamonds from the bulk samples at several site streams contained diamonds that have been reported by Kaminsky 1996 to have been derived from a nearby bedrock source. The Diamonds are of large size and have surface features that are easily removed by transport.
|2006 to 2007||Paramount Mining Corporation Ltd (Leo Shield JV) carried out repeat test pitting and trenching at the Cornucopia sites with a program of stream sediment sampling and 90km of soil sampling traverses/grids for Gold exploration.|
|2007 to 2012||Paramount Mining and 2012 Leo Shield Stream Sediment Sampling Programs. Systematic program of “stream samples” collection from paleo gravels adjacent to drainages. 466 sites sampled giving 242 samples, including 9 duplicates at Osenase (Leo Shield). 134 samples including 7 duplicates at Asamankese (Leo Shield) and 108 samples including 2 duplicates at Asamankese (Paramount).|
Over the Birim concessions area lithological units are dominated by intercalated sequences of Birimian Volcanic and meta-sedimentary units which have been intruded by significant occurrences of basin type granitoids. In addition, and of particular interest, local over the Osenase area ultramafic units have been observed to occur as intermingling with local undifferentiated volcanic sequences. All units have undergone sustained weathering, degradation and oxidation. Locally it is the ultramafic or ultrabasic units that are believed to be the source of the majority of the alluvial diamonds found in the immediate district.
Further north the local geological domain is dominated by intercalated sequences of Birimian Volcanic and meta-sedimentary units, which have to a lesser extent intruded by minor occurrences of basin type granitoids and ultrabasic lithologies.
The World Bank undertook reduced to pole geophysics to assess the regional potential over the central zone of the Kibi-Winneba belt. The Diamond and Gold anomalism broadly coincides with local geophysical signatures. The World Bank also undertook magnetic and radiometric surveys over the belt. The Gold anomalism broadly clearly coincides with local high magnetic signature, whereas the Diamond anomalism coincides with radiometric lows.