MTONYA PROJECT
Mtonya Project Geology
Mtonya leases and general geology
The Mtonya leases cover the contact between the Usagaren basement to the west and the Karroo Luwegu Basin to the east. The Usagaren basement is interpreted to be the source of the uranium mineralization with the porous sandstone units of the Karroo formation hosting redox style mineral enrichments.
Uranium deposits of the sandstone-type targeted in the Luwegu Basin comprise more than 30% of currently known uranium deposits in Africa, including Paladin’s Kayelekera deposit 200km to the west in Malawi that contains a reported resource of 13,630 tonnes of uranium oxide and is hosted by the Karroo formation.
The Mkuju Prospect, discovered in 1978, located approximately 40 kilometres to the north and east of the tenements is the targeted model of mineralization for the Mtonya area. The Mkuju Prospect has returned near surface channel and trench samples up to 2.18% U3O8 and shows that significant amounts of uranium have been mobilized from basement rocks and were precipitated within the reduced fluviatile sandstones of the Karoo formation. The uranium enrichment at Mkuju extends over an area of 5x3 km that indicates that the “uranium front” is large enough to generate ore bodies.
Airborne radiometric data shows that the granites and gneisses of the Usagaren are fertile for uranium and therefore present a source rock for redox style deposits. This implies that the whole of the western margins of the Karroo sediments including any palaeo-channels cut into the basement are prospective for uranium. If at any stage reducing conditions have prevailed, then extensions or repetitions of the known uranium mineralization are possible. The Mtonya project area covers a substantial part of this target zone. A secondary, speculative target is hydrothermal vein and/or metasomatic type uranium mineralization in the Usagaren basement. Such mineralization has not been reported from the area but there are reports of radioactive minerals being found in artesian gemstone operations within Tanzania which supports the possibility of hydrothermal uranium mineralization.
Previous Exploration
Previous exploration of the Mtonya area comprised broad scale regional mapping and airborne radiometric and magnetic surveys. These surveys were conducted in the 1970’s using 1kilometer spaced flight lines. The airborne surveys identified many anomalies over the tenement area however ground based field testing was not conducted. Interpretation of the survey data indicates that the anomalous zone extends for approximately 7 kilometers over the tenement area.
Recent Exploration
Detailed evaluation of the historic airborne radiometric data was conducted in early 2006 with many anomalies identified and ranked based on their response above background level and the consistency of response along the flight line.
In April 2006 field reconnaissance was conducted by Dr. Joe Drake Brockman to validate one of the strongest radiometric anomalies. A limited hand held scintillometer survey in the immediate area of the airborne anomaly yielded an anomalous zone measuring 20 metres long with an apparent thickness of 1.5 m located on the top of a dissected ridge within brown soils above subcrop of coarse grained cross bedded reduced sandstones. A 500 counts per second (cps) threshold was used to approximate the edge of the anomalous zone. Maximum readings on the surface were 10,000 cps increasing to off scale (>15,000 cps) in a 20 cm deep sample hole. Weaker anomalies in the range 150-500 cps were also located in general area.
Four samples were collected in the anomalous zone with all confirming the presence of uranium and low levels of thorium. The peak U3O8 assay result was 980ppm with traces of yellow secondary uranium mineralization noted in that sample. The anomaly has been named Henri. Figure 3 shows the approximate extent of the airborne radiometric anomaly and the location of the peak sample.
Planned Exploration
Field exploration will be conducted in August and September 2006. The focus of the work will be the Henri anomaly and surrounds in the South-East lease. A total of 10 airborne anomalies will be checked over the 7 kilometer long trend of anomalies identified by the historic airborne radiometric survey.
The field work will consist of extensive ground based radiometric traverses to confirm the size, continuity and magnitude of the anomalies, sampling of hotspots to verify uranium mineralization, trenching of mineralized zones to estimate thickness and orientation, and geological mapping of trenches and outcrops to establish the parameters controlling the mineralization. It is anticipated approximately 15-20 trenches will be excavated and approximately 1,000 sample collected.
The two other rank 1 anomalies in the Main lease will also be investigated and sampled and any rank 2 anomaly that is readily accessible will also be assessed. The basic geological parameters will be mapped and the presence of the postulated sedimentary channels will be investigated. Data collected from this field work will be collated and interpreted and if successful in confirming the presence of widespread uranium mineralization, it will be used to design an initial drilling program and detailed airborne radiometric survey.