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Thambani

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 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
Trench
No.
Profile Sample
No:
From
(m)
To
(m)
Rock type U308
ppm
Nb2O5
ppm
Ta2O5
ppm
C3
C3
T11
T11
T11
T15
T15
T15
T14
T19
A
A
C
C
B
A
A
E
D
C
U3622
U3623
U3508
U3509
U3505
U3554
U3553
U3565
U3549
U3604
0.5
1
0.5
1
0.5
1
0.5
0.5
1.5
1
1
1.5
1
1.5
1
1.5
1
1
2
1.5
Soil
Soil
Decomposed Feldspathic rock
Decomposed Feldspathic rock
Decomposed Feldspathic rock
Feldspathic rock
Feldspathic rock
Feldspathic rock
Feldspathic rock
Feldspathic rock
47,094
1,057
4,231
2,539
2,369
1,657
1,616
1,553
1,432
1,367
32,462
735
7,805
6,619
5,424
4,346
3,754
3,525
3,034
5,525
45
59
743
911
972
67
431
41
434
675


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
Sample no. U3O8 ppm U3O8 % Ta2O5 ppm Ta2O5 % Nb2O5 ppm Nb2O5 %
U3141 32590 3.26 19029 1.90 59200 5.92
U3183 31812 3.18 15224 1.52 60055 6.01
U3136 10131 1.01 4845 0.48 32478 3.25
U3111 8826 0.88 4191 0.42 14871 1.49
U3127 5468 0.55 3084 0.31 15138 1.51
U3135 5265 0.53 2747 0.27 13183 1.32
U3122 5250 0.52 2431 0.24 10820 1.08
U3125 4518 0.45 2028 0.20 8461 0.85
U3115 4352 0.44 2221 0.22 9789 0.98
U3121 4191 0.42 2390 0.24 13585 1.36
U3137 3988 0.40 1896 0.19 8707 0.87
U3124 3952 0.40 2100 0.21 9600 0.96
U3168 3664 0.37 2022 0.20 7137 0.71
U3129 3562 0.36 1625 0.16 6469 0.65
U3176 3264 0.33 1905 0.19 5864 0.59
U3131 2768 0.28 1293 0.13 5314 0.53
U3133 2231 0.22 1235 0.12 5971 0.60
U3118 2163 0.22 1330 0.13 3838 0.38
U3172 1749 0.17 1351 0.14 3924 0.39
U3119 1741 0.17 916 0.09 4592 0.46


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