Kilo Goldmines (CVE:KGL) unveiled Thursday what it called "encouraging" results from preliminary metallurgical test work on diamond drill core from its Adumbi gold deposit, part of the Somituri project in northeastern Democratic Republic of Congo (DRC).
Overall recoveries were 94.2 percent for gold recovery in oxide and 96.2 percent for gold recovery in sulphide.
The company said fold recoveries for three oxide composite samples
ranged from 92.2 to 94.3 percent by gravity concentration, followed by
cyanide leach of the gravity tails.
The gold recovery for one sulphide composite sample, which originated
at depth from a minor lithological formation, was 42.9 percent, while
two other composite samples returned gold recoveries of 92.5 percent and
The company said it will undertake further testing to optimize
overall recoveries, including conventional cyanide leach testing on
gravity tailings to improve grind size and solution strength. UK-based
Wardell Armstrong prepared composite samples and carried out the test
"The preliminary test work is very encouraging and indicative that in
excess of 90% of the gold in the oxide appears recoverable by the
simple process of gravity and cyanide leaching of gravity concentration
tails," said president and CEO, Alex van Hoeken.
"Given that the recent Inferred Mineral Resource estimate concluded
about 600,000 ounces of gold in oxide, most of which is contained within
Adumbi Mountain and mineable by open-pit with a very low stripping
ratio, the anticipated ease of gold recovery is expected to bode well
for the project economics."
In mid-March, Kilo released an updated NI 43-101 resource estimate
for its 71.25 percent-owned Adumbi deposit. The DRC-focused gold
explorer said in the inferred category, at a cut-off grade of 0.5 grams
per tonne (g/t) gold, the resource estimate comprises 35.6 million
tonnes containing 1.87 million ounces of gold at an average grade of
1.63 g/t gold. Of this, 33 percent is attributable to oxide, while 53
percent is attributable to sulphide.
Hoeken added: "The gold recoveries in excess of 90% for two of the
three sulphide samples are most encouraging in that the majority of the
sulphide mineralization may also be amenable to gravity and cyanide
leaching of gravity concentration tails, in particular when the third
sulphide sample is referenced to its host lithology that represents less
than 4% of the gold bearing rock types identified in the Adumbi Gold
"Furthermore, the lower than expected Bond Mill Working Indices
should have a favourable impact on the power and infrastructure
requirements for the project."
Indeed, the Bond Mill Working indice for composite oxide was 10.5
kilowatt hours per tonne (kWh/t), below expectations, and the indice for
composte sulphide was 11.3 kWh/t, also below estimates.
Bond Ball Mill Work indices tests were carried out on one composited
oxide sample, and on one composited sulphide sample. The test work has
not conclusively determined the indices for the various rock types
hosting the gold, the company said, but preliminary indications are that
they are "significantly lower than expected".
As a result, this means an unexpected positive for process selection
while possibly lower than expected project power requirements will be
For the metallurgical testing, Kilo submitted 191 samples of diamond
drill core from seven drill holes. The four oxide samples cover a strike
length of 480 metres and the three sulphide samples were selected over a
strike length of 560 metres and to a maximum vertical depth of 275
metres below surface.
is a Canadian gold exploration company that has over 7,000 square
kilometres of Archaean Kabalian greenstone in the Kilo-Moto area of the
DRC. It also has a joint venture with Rio Tinto (NYSE:RIO) on potential iron ore licences in north-eastern DRC