Mr. Benjamin Cohen reports
ROBEX RESOURCES INC.: WITH 391,000 OUNCES OF PROBABLE MINERAL RESERVES, ROBEX EXPECTS A MINE LIFE OF NEARLY 9 YEARS FOR NAMPALA
Robex Resources Inc. has filed with SEDAR the technical report titled "NI 43-101 Technical Report, Mineral Resource and Mineral Reserve Estimates for the Nampala Gold Mine (2020)" signed and dated Oct. 23, 2020.
The latest mineral resource estimate (2020 MRE) and the mineral reserve estimate (2020 MR) are summarized herein. They required an update for the following motives:
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The Nampala phase 4, containing 410 drill holes, added a total of 34,998 metres to the geological database. These drill holes were mainly drilled east of the current open pit.
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The price of gold has increased significantly in the last year. The last mineral resource estimate (2019 MRE) used a price of gold of $1,250 (U.S.) per ounce. This value was increased to $1,700 (U.S.) per oz for the 2020 MRE and to $1,500 (U.S.) per oz for the 2020 MR.
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The density model was updated to take into account the results from the mine-to-mill mass balance completed in 2020.
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Mineralized material contained in the upper transition weathering horizon was metallurgically tested in 2019/2020. The average tests returned some suitable recovery rates of 86.8 per cent and 88.0 per cent for two sampled populations.
Mineral resource estimate (2020 MRE):
On July 31, 2020, the mineral resource in the indicated category was estimated at 37,887,000 tonnes at a grade of 0.71 gram per tonne gold and a metal content of 869 000 oz of gold. The mineral resource in the inferred category was estimated at 2,989,000 t at a grade of 0.69 g/t Au and a metal content of 66 000 oz of gold. The presented mineral resource includes the mineral reserve.
MINERAL RESOURCE ESTIMATE (2020 MRE)
Category Cut-off Weathering Tonnage (000 t) Grade Au (g/t) Metal content Au (000 oz)
Au (g/t) type
Indicated 0.25 Oxide 21,422 0.63 435
0.33 Transition 6,158 0.82 163
0.31 Fresh rock 10,307 0.82 271
Subtotal 37,887 0.71 869
Inferred 0.25 Oxide 542 0.55 10
0.33 Transition 213 0.71 5
0.31 Fresh rock 2,235 0.72 52
Subtotal 2,989 0.69 66
Total 40,876 0.71 936
Notes:
1. The independent and qualified persons for the mineral resource estimate, as defined by National Instrument
43-101, are Denis Boivin, BSc, Geo (OGQ No. 816), and Mario Boisse, mining engineer (OIQ No. 130715), and the
effective date of the estimate is July 31, 2020.
2. The mineral resource is not a mineral reserve as it has not demonstrated economic viability. Further
metallurgical testing is required to analyze the economic potential of the mineral resource found in the
transition and fresh rock zones.
3. The mineral resource estimate follows the 2014 CIM (Canadian Institute of Mining, Metallurgy and Petroleum)
definitions and guidelines.
4. Results are presented on site and undiluted for the open-pit scenario and are considered to have reasonable
prospects for profitable mining.
5. In terms of classification, the distance to the closest (composite) point (DCP) must be fewer than or equal
to 30 metres to be considered an indicated resource. The inferred resource is at a distance greater than 30
metres and fewer than 100 metres.
6. Grade interpolation was performed on the Nampala mining permit from two-metre drill composites using the
grade of the material assayed and clipped at 15 grams per tonne gold. The grade model was interpolated
according to the structural patterns of the mineralized zones using the Leapfrog Geo Version 5.1.0 software
radial basis function (RBF) method and assessed in a model pointed at 20 degrees north with blocks of the same
size (five metres by 15 metres by five metres). On-site densities were interpolated using the respective
oxidation levels.
7. The mineral resource is contained within an economic envelope built with the MineSight project evaluator
Version 1.0.4.3902 Lerch-Grossman optimization tool. Only the indicated resource is taken into account to
generate the economic envelope.
INPUT ASSUMPTIONS USED FOR CUT-OFF GRADE ESTIMATE
OF MINERAL RESOURCE ESTIMATE
Assumptions UOM Oxide Transition Fresh rock
Gold price U.S.$/oz $1,700
Mining cost U.S.$/t mined $2.08 $2.51 $2.65
G&A cost U.S.$/t milled 2.48 2.48 2.48
Processing cost* U.S.$/t milled 9.31 10.24 -
Heap leach cost* U.S.$/t milled - - 9.19
Mill recovery % 88.9 71.9 -
Heap leach recovery % - - 70
Optimizer cut-off grade g/t 0.25 0.33 0.31
* Includes transport and refining cost.
8. The slope of the economic envelope is set to 45 degrees.
9. The number of metric tonnes has been rounded to the nearest thousand,
and the metal grade is presented in troy ounces (tons times grade
divided by 31.10348). Any discrepancies between totals are due to
rounding effects. Rounding practices comply with the recommendations
outlined in Form 43-101A1.
10. Except for the political instability in Mali and the current
COVID-19 pandemic, Denis Boivin, PGeo, and Mario Boisse, Eng, are not
aware of any environmental, permit, legal, title-related, fiscal,
socio-political or marketing issues, or any other relevant issues that
could have a significant impact on the mineral resource estimate.
Mineral reserve estimate (2020 MR)
On July 31, 2020, the mineral reserve was estimated at 17,147,000 tonnes of oxidized ore and upper transition, with a metal content of 391 000 oz of gold. The average grade was 0.71 g/t using a cut-off of 0.28 g/t in the oxide and 0.31 g/t in the upper transition. The mineral reserve estimate (2020 MR) presents a life of mine of almost nine years.
NAMPALA MINE PROBABLE MINERAL RESERVE
Weathering type Probable mineral reserve
Cut-off Au Tonnage Grade Au Metal content Au
(g/t) (000 t) (g/t) (000 oz)
Oxide 0.28 15,291 0.69 339
Upper transition 0.31 1,857 0.87 52
Lower transition n/a
Fresh rock n/a
Total 17,147 0.71 391
Notes:
1. The independent and qualified persons for the mineral reserve estimate,
as defined by National Instrument 43-101, are Denis Boivin, BSc, Geo (OGQ
No. 816), and Mario Boisse, mining engineer (OIQ No. 130715), and the
effective date of the estimate is July 31, 2020.
2. Reported in accordance with Canadian Institute of Mining, Metallurgy
and Petroleum (CIM) standards.
3. Constituted of oxide and upper transition ore only.
4. Based on a pit shell that does not include inferred material. In that
case, the DCP must be inferior or equal to 30 metres to be considered
indicated.
5. Classified as probable.
6. Included in the mineral resource.
7. Identified as minable using standard open-pit mining only.
8. Located within seven pit designs based on a pit shell.
9. Excluding lower transition and fresh rock mineralization as current ore
processing infrastructures may be unsuitable if the ore is refractory or
too hard for the current processing equipment. For calculation purposes,
the recovery was set at 0 per cent for lower transition and fresh rock,
which is very conservative.
10. Taking into account a mining recovery of 97 per cent.
11. Assuming a dilution factor of 0 per cent based on the composites used
to interpolate the grade in the block model, the current ore control
process, the mining method and the ore body characteristics.
12. Excluding any pit design that would be smaller than 100 m in diameter.
13. Used as a base for the life-of-mine (LOM) production plan.
14. Grade interpolation was performed on the Nampala mining permit from
two-metre drill composites using the grade of the material assayed and
clipped at 15 g/t Au. The grade model was interpolated according to the
structural patterns of the mineralized zones using the Leapfrog Geo Version
5.1.0 software radial basis function (RBF) method and assessed in a model
pointed at 20 degrees north with blocks of the same size (five m by 15 m by
five m). On-site densities were interpolated using the respective oxidation
levels.
15. The mineral reserve is contained within the seven pit designs. The base
for the pit designs is an economic envelope built with the MineSight
project evaluator Version 1.0.4.3902 Lerch-Grossman optimization tool.
INPUT ASSUMPTIONS USED FOR CUT-OFF GRADE ESTIMATE
OF MINERAL RESERVE ESTIMATE
Assumptions UOM Oxide Upper transition Lower transition Fresh rock
Gold price U.S.$/oz $1,500
Mining cost U.S.$/t mined $2.08 $2.51 $2.51 $2.65
G&A cost U.S.$/t milled 2.48 2.48 2.48 2.48
Processing cost* U.S.$/t milled 9.31 10.24 10.24 -
Heap leach cost* U.S.$/t milled - - - 9.19
Mill recovery % 88.9 86.0 0 -
Heap leach recovery % - - - 0
Optimizer cut-off grade g/t 0.28 0.31 - -
* Includes transport and refining cost.
16. The slope of the economic envelope is set to 40 degrees for the first 20 m and then follows
an angle of 45 degrees.
17. The number of metric tonnes has been rounded to the nearest thousand, and the metal grade
is presented in troy ounces (tons times grade divided by 31.10348). Any discrepancies between
totals are due to rounding effects. Rounding practices comply with the recommendations outlined
in Form 43-101A1.
Denis Boivin, PGeo, on-site consulting geologist, is the qualified and independent person under NI 43-101, who has reviewed and approved the disclosure of the geological information contained in this press release.
Benjamin Cohen, chief executive officer of Robex, said: "I would
like to
thank the technical teams who have done an
unbelievable job in particularly difficult conditions with COVID-19
and
a terrible rainy season that has
caused
delays.
"We are very pleased with these first results for our shareholders, employees and village communities
because the horizon has been pushed back.
"The exploration work continues very
intensely. We are confident about the
future.
We
are
awaiting
results
for
the southern and western
areas
in particular.
"The work carried out has already allowed us to open a second pit that will provide a second source of ore to stabilize the production grade.
"Restoring a satisfactory mine life was one of our main objectives.
This
creates value
and confidence to find more gold in the near future."
About Robex Resources Inc.
Robex is a Canadian mining company, operating in gold production and exploration in West Africa. The company operates the Nampala mine in Mali, which reached the commercial production stage on Jan. 1, 2017.
We seek Safe Harbor.
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