|The Thambani exploration licence, located in the Mwanza District, was originally granted by the Malawi Minister of Natural Resources, Energy and Environment on September 10, 2010 in respect of an area of 468km2. In September 2013, September 2015 and September 2017 the Government of Malawi granted further two year renewals for the licence. At the second renewal the Company requested a reduction in the licence size to the current area of 136.9km2 .|
Mkango's exploration activities to date include acquisition of Landsat7 and ASTER satellite imagery for the licence area, systematic ground radiometric surveys to confirm and detail previously-known airborne anomalies, reconnaissance geological mapping and litho-geochemical sampling programs. The work has identified a number of potential uranium and associated Nb-Ta targets over the Thambani Massif, which is mainly composed of nepheline-bearing syenite gneiss, forming two prominent ridges known as Thambani East Ridge and West Ridge.
A systematic ground radiometric survey completed by Mkango previously revealed two distinct uranium anomalies occurring across the Thambani East and West Ridges: A strong uranium anomaly, measuring approximately 3km by 1.5km, occurs along the length of the Thambani East ridge, with a north-south trend, and a second uranium anomaly, measuring approximately 1.5km by 0.4km, occurring on the West Ridge along the western contact of the nepheline-bearing syenite body with the biotite-hornblende gneisses.
Mkango completed a trenching program across the Thambani Massif primarily focused on two sites of historical uranium exploration, known as the Chikoleka and Little Ngona targets. An initial set of 9 trenches, selected on the basis of anomalous ground radiometric results, have been re-examined and geochemically sampled across profiles from soil/overburden into bedrock.
The first set of assay results of 142 soil and rock chip samples returned variably anomalous U, Nb and Ta values in most trenches, ranging up to 4.70 per cent. U308, 3.25 per cent. Nb2O5 in soil and up to 0.42 per cent. U308, 0.78 per cent. Nb2O5 and 972 ppm Ta2O5 in rock chips, notably higher than results from the 2013 reconnaissance surface geochemical sampling program. Results associated with the 10 best U308 assays are summarized in Table 1.
Preliminary mineralogical studies carried out on six rock samples from the Little Ngona River and Chikoleka targets, using SEM at the Natural History Museum London, indicate that pyrochlore group minerals, mainly betafite, are the principal carriers of U, Nb and Ta for these samples.
Assays from the 10 highest - U308 samples from the Thambani trenching program
A further exploration and sampling programme was undertaken during April 2017. Assay results from 85 rock grab samples returned high grade uranium, tantalum and niobium values, ranging up to 3.3 % U308, 1.9 % Ta2O5 and 6.0 % Nb2O5. 35 of the samples graded above 500ppm U308 and 24 graded above 1,000ppm U308. Results associated with the twenty best U308 assays are summarised in the table below.
The main objectives of the programme were to confirm previously identified high grade mineralisation at the Little Ngona target, ground-truth new geophysical targets and complete further reconnaissance sampling along the East and West Ridges.
New areas of high grade uranium, tantalum and niobium mineralisation were identified at the foot of the West Ridge and on the East Ridge. Most significantly, a radiometric high at the foot of the West Ridge yielded two of four highest grade samples of this phase of exploration.
Assays from the 20 highest grade U308 samples from the Thambani sampling programme
Sampling was primarily focused on zones of anomalous uranium and associated niobium and tantalum targets across the Thambani Massif, a nepheline-bearing syenite gneiss which dominates the north-eastern part of the licence. Grab samples are selective samples and are not necessarily representative of the mineralization hosted on the property. The average grades for the 85 samples were 1,892 ppm U308, 1,029 ppm Ta2O5 and 4,562 ppm Nb2O5. The median grades for the 85 samples were 343 ppm U308, 222 ppm Ta2O5 and 958 ppm Nb2O5. The ranges of grades for the 85 samples were 1 - 32,590 ppm U308, 2 - 19,029 ppm Ta2O5 and 0 - 60,055 ppm Nb2O5.
Mkango is currently evaluating strategic options for Thambani, including opportunities to joint venture or spin-off the project, and other potential avenues to create value.
|Results of Airborne Radiometric Survey|
Results of Airborne Magnetic Survey