Mkango Resources reports results from recent Thambani exploration
Mkango Resources announced results from its recent mineral exploration programme at the Thambani project in southern Malawi on Wednesday, reporting that assay results from 128 rock samples collected during the 2019 exploration programme returned uranium, tantalum and niobium values ranging up to 0.74% triuranium octoxide, 0.41% tantalum pentoxide and 3.24% niobium pentoxide.
The AIM-traded firm said that of the total, 43 graded above 500 parts per million triuranium octoxide, of which 13 graded above 1,000 parts per million, with all but one of those 43 samples being in-situ rock samples.
It said the objective of the programme was to identify new areas of outcropping mineralisation through further geological reconnaissance and sampling, guided by handheld spectrometer.
Sampling was focussed on the uranium anomalies identified by previous airborne and ground radiometric surveys, including areas where previous sampling gave “encouraging” results.
The aims of the sampling was to better delineate the mineralised zones, and to localise future drill sites to test the downdip extension of surface mineralisation, the board explained.
It said field observations and sampling results suggested that mineralisation occured in zones that were conformable with gneissic banding.
“The 2019 sampling programme was focused on radiometric uranium anomalies associated with the Thambani Massif, a body of nepheline-bearing syenite gneiss which dominates the north-eastern part of the licence,” the board said in its statement.
“Previous work has shown the uranium anomalies to be associated with niobium and tantalum mineralisation.”
Two suites of samples were collected, with the first being in-situ grab samples from outcrop, and the second being extremely friable, highly weathered rock from trenches that were manually excavated to approximately 10 metres long, 1.5 metres wide and two metres deep, and oriented west to east across the regional strike of the gneissic foliation.
Grab samples were selective, and were not necessarily representative of the mineralisation on the property, the company explained.
It said 58 surface grab samples were collected, 54 of which were from outcrop associated with the prominent radiometric anomaly along the western slope of the East Ridge, and four from outcrop in the Supe River.
“Ten trenches were excavated by hand over radiometric anomalies,” Mkango said.
“Three of these - the Western Trenches - were spaced 25 metres apart, immediately adjacent to a pit where the highest grades were encountered in 2017.
“The seven other trenches were excavated over radiometric anomalies at widely separated locations on the lower slope of the East Ridge.
“In all of the trenches, highly weathered nepheline syenite gneiss was encountered below a bouldery soil horizon approximately 0.5 metres thick.”
Mkango said the westward dip of the banded gneiss observed in outcrop on the ridges was recognisable in the trenches despite strong weathering.
In the Western Trenches, 70 samples were collected, 61 of which were horizontal channel samples of two metres length collected along each wall in all of the three trenches.
Five similar samples were collected in one trench at the foot of the East Ridge.
The assays showed that grades in the fresh rock tended to be higher, suggesting extensive secondary remobilisation of the elements of interest, the board said.
“This programme provides new information on the nature, disposition and grade ranges of mineralisation in the Thambani Massif.
“Sampling of mainly fresh samples on the East Ridge indicates that the U-Ta-Nb mineralisation occurs within the gneissic bands, and surface observations indicate that it may occur in conformable zones.”
That, the company said, provided a target for shallow drilling on the down-dip extension of the surface showings.
“Mkango is currently evaluating strategic options for Thambani, including opportunities for joint venture and other potential avenues to create value.”
At 1449 GMT, shares in Mkango Resources were down 3.11% at 7.8p.