Continuous Surface Mining Scenario to Be Contemplated in Economic
Assessment of U3O8 Corp's Laguna Salada Deposit in Argentina for a
Potential Low-Cost Project
Continuous Surface Mining Scenario to Be Contemplated in Economic
Assessment of U3O8 Corp's Laguna Salada Deposit in Argentina for a
Potential Low-Cost Project
TORONTO, ONTARIO--(Marketwired - Sep 26, 2013) - U3O8
Corp. (TSX:UWE)(OTCQX:UWEFF), a
Canadian-based company focused on exploration and resource
expansion of uranium and associated commodities in South America,
outlines the positive beneficiation work and one potential mine
concept being considered in the Preliminary Economic Assessment
("PEA") that is underway on the Laguna Salada Deposit in Chubut
Province, Argentina.
"Given the project's simplicity and the proposed joint venture
with Petrominera Chubut S.E., Chubut's provincial mining company,
U3O8 Corp's Laguna Salada Deposit is shaping up to be a potentially
near-term, low-cost uranium producer that could help Argentina
reduce its 100% reliance on imported nuclear fuel," said Dr.
Richard Spencer, U3O8 Corp's President and CEO. "The continuous
surface mining option being assessed in the PEA would be by
machines very similar to those that cut and lift old asphalt from
roads that are being repaved. One could picture the continuous
surface mining concept as a long shallow trench that migrates
sideways across a gravel plain with gravel being removed from the
leading edge of the trench, washed, and replaced on the trailing
edge. This mining option would be expected to see 95% of the
original gravel returned to the excavated area, reshaped to its
original topography and revegetated with shrubs transplanted from
the advancing side of the trench. After mining, there would be
little evidence that mining had occurred."
Continuous
Surface Mining Scenario
The Laguna Salada Project is a near-surface, free-digging
deposit on which an initial uranium-vanadium resource has been
defined in accordance with National Instrument 43-101 ("NI
43-101"). Mineralization lies within three metres ("m") of surface
in soft, pebbly gravel that requires no blasting before mining and
no crushing prior to beneficiation (Figure 1). The soft gravel
could be excavated with a continuous surface miner, which is the
preferred option being contemplated in the PEA expected for release
in Q4 2013, and is expected to work as follows (Figure 2):
- Vegetation and the thin soil layer would be removed from the
area to be mined and temporarily stored to make way for a
continuous surface miner, such as a Wirtgen 2500.
- A continuous surface miner would cut a long, narrow trench that
would advance sideways across the flat-topped gravel mesas in one
direction while being refilled with washed gravel from the other.
The trench would be up to 3m deep, the maximum depth of the NI
43-101 resource, and about 20m-30m wide at any one time.
- The gravel would be lifted from the continuous miner into 100
tonne truck-trailer units via a conveyor belt. Barren gravel would
be immediately returned to the trailing edge of the trench, while
the mineralized gravel would be trucked to a mobile screening
plant.
- The mineralized gravel would be washed through progressively
finer sieves to a 0.15 millimetre ("mm") grain size. The pebbles
and sand that is coarser than 0.15mm (approximately 90% of the
original gravel mass) would be transported back and tipped into the
excavated area to await final shaping to its original
topography.
- Test work on the Guanaco area, which contains 90% of the Laguna
Salada resource, showed that screening concentrates approximately
87% of the uranium into the fine material, which constituted about
10% of the gravel's original weight. These metal-rich fines would
be mixed with water and pumped through a pipeline to a central
processing facility for further concentration through a system of
hydrocyclones This additional process resulted in the concentration
of approximately 80% of the gravel's original uranium content into
about 5% of the gravel's original mass. Only water is used in the
beneficiation of the gravel in the screening and hydrocyclone
steps.
- The 5% of the fines rejected by the hydrocylones would be
pumped back to the excavated area. As a result, approximately 95%
of the original gravel mass (90% from the screening process plus 5%
from the hydrocyclones) would be returned to the mined area to be
covered with soil and revegetated with the plants removed prior to
mining.
- The uranium-vanadium - bearing material would then undergo
alkaline leaching with a solution containing a mixture of baking
soda (sodium bicarbonate) and washing soda (sodium carbonate).
Improved
Beneficiation Results with Hydrocyclones
Test work showed that passing the fine material in the Guanaco
sector from the screening process through hydrocyclones isolated
the mineralization into a small fraction of the original mass,
resulting in a very large increase in grade. A hydrocyclone is a
cone-shaped device that has no moving parts and is designed to
separate light, fine-grained particles from larger, heavier ones. A
mixture of water and silty material from the gravel at Laguna
Salada was pumped into the cone in a way that ensures that the
mixture swirls inside the cone. The heavier and larger particles
are thrown against the side of the cone where they slide downward
and are removed from an aperture in the bottom of the cone
(underflow). The finest-grained, uranium-bearing material
concentrates in the centre of the cone where it gradually moves
upward under slight pressure and is removed through a pipe in the
top of the hydrocyclone (overflow).
A composite sample from three trenches in the Guanaco sector of
the Laguna Salada Deposit was specifically selected for test work
to ensure that low-grade material had beneficiation characteristics
similar to the higher-grade gravel. 42.2 kilograms of gravel was
wet-scrubbed in a cement mixer for one hour, then wet screened
through successively finer sieves starting with a 15mm aperture
followed by screens with 3mm, 0.84mm, 0.5mm and finally 0.15mm or
150?m apertures. The material finer than 150?m was further
separated into coarse and fine fractions using a hydrocyclone.
Table 1 shows the resulting mass of each grain size fraction with
its uranium and vanadium grade, and the proportion of metal
contained in each fraction.
This wet screening followed by hydrocyclone beneficiation
resulted in the concentration of approximately 80% of the uranium
and 18.6% of the vanadium contained in the gravel into 5.3% of its
original mass. The grade of the composite sample used in this test,
as excavated from site, was 23ppm U3O8 and
after beneficiation, the uranium grade of the fine material was
358ppm U3O8 - an increase of 15 times (Table
1). Vanadium grades increased from 350ppm
V2O5 in the gravel to 1,250ppm in the fine
material - an increase of 3.5 times. These test results lead U3O8
Corp. to believe that the average uranium grade of 55ppm
U3O8 in the Guanaco sector of the Laguna
Salada Deposit might be beneficiated to a grade of approximately
825ppm (1.8lb/tonne) U3O8 and for vanadium,
from 530ppm V2O5 to about 1,850ppm
V2O5 if similar results can be achieved.
Previous test results (September 21, 2011 press release) showed
that wet-screening of higher-grade gravel from the Guanaco area led
to an 8-11 times increase in uranium grade to approximately
620-670ppm1 in the 150?m fraction, without the use of
hydrocyclones. Test work is currently underway to verify that
adding the hydrocyclone step in the beneficiation of higher-grade
material generates similar results to those achieved in the
low-grade sample from Guanaco. Results from this additional test
work will be reported shortly.
Alkaline Leach
Test Results
Prior test work (September 21, 2011 press release) on fine
material generated from screening the gravel to a 0.15mm grain size
showed extraction of approximately 94% of the uranium and 51% of
the vanadium contained in the fines. Alkaline leach test work on
the finer material resulting from the use of hydrocyclones in the
beneficiation process will be reported on shortly.
Table 1 - Summary
Results for Screened and Hydrocycloned Laguna Salada
Sample |
|
|
|
|
Uranium
(U3O8) |
Vanadium
(V2O5) |
Size
fraction
(?m) |
Mass
(g) |
% of
material
retained
between
successive
screen sizes |
Assay
(ppm) |
Distribn
(%) |
Assay
(ppm) |
Distribn
(%) |
Raw gravel |
42,247 |
|
23 |
|
350 |
|
15,000 |
10,980 |
26.0% |
6.1 |
7% |
256 |
19% |
3,000 |
20,780 |
49.2% |
2.0 |
4% |
367 |
50% |
840 |
1,260 |
3.0% |
4.1 |
1% |
272 |
2% |
500 |
840 |
2.0% |
3.6 |
0% |
114 |
1% |
150 |
4,260 |
10.1% |
2.8 |
1% |
160 |
5% |
Hydrocyclone overflow
(fine material to undergo leaching) |
2,247 |
5.3% |
357.8 |
80% |
1,250 |
18.6% |
Hydrocyclone underflow
(rejected coarser material) |
1,880 |
4.5% |
40.0 |
7% |
409 |
5% |
Total |
42,247 |
100.0% |
|
The conceptual continuous surface mining method described above
was developed by Mr. Pedro Pino Veliz, a Qualified Person ("QP") as
defined by NI 43-101. Mr. John Goode, P. Eng. and a QP, has
reviewed the beneficiation and metallurgical test work on Laguna
Salada. The beneficiation test work was carried out at the
University of San Juan in Argentina and assays were conducted by
SGS del Peru S.A.C. in Lima, Peru. Dr. Richard Spencer, President
& CEO of U3O8 Corp. and a QP, has supervised the preparation
of, and verified the technical information contained in this press
release.
Mineral resources that are not mineral reserves do not have
demonstrated economic viability. The PEA, once prepared, will be
preliminary in nature and will include inferred mineral resources
that are considered too speculative geologically to have the
economic considerations applied to them that would enable them to
be categorized as mineral reserves. There is no certainty that the
PEA will be completed at all and if completed, will be
realized.
About U3O8
Corp.
U3O8 Corp. is an advanced exploration company focused on
exploration and resource expansion of uranium and associated
commodities in South America. From 2010 to 2012, U3O8 Corp's
uranium resources grew 7-fold with three NI 43-101 deposits defined
in Colombia, Argentina and Guyana comprising of:
- Berlin Deposit, Colombia - a recent PEA shows
that Berlin could be a zero cash cost uranium producer thanks to
revenue from by-products of phosphate, vanadium, nickel, rare
earths (yttrium and neodymium) and other metals occurring in the
same deposit;
- Laguna Salada Deposit, Argentina - a near
surface, free-digging uranium, vanadium deposit that is potentially
amenable to low-cost mining and processing methods; and
- Kurupung Deposit, Guyana - an initial uranium
deposit in a large emerging uranium district.
Additional information on U3O8 Corp., its mineral resources and
technical reports are available at www.u3o8corp.com. The May 20,
2011 technical report on the Laguna Salada Deposit entitled "Laguna
Salada Project, Chubut Province, Argentina: NI 43-101 Technical
Report: Initial Resource Estimate" (the "Technical Report") is also
available on SEDAR at www.sedar.com. Follow U3O8 Corp. on Facebook:
www.facebook.com/u3o8corp, Twitter: www.twitter.com/u3o8corp and
Youtube: www.youtube.com/u3o8corp. Below is the NI 43-101 resource
estimate on Laguna Salada as contained in the Technical Report:
Project |
NI 43-101
Resource |
Tonnes
(million) |
Grade
U3O8 |
Grade
V2O5 |
U3O8 lbs
(million) |
V2O5 lbs
(million) |
Laguna Salada |
Indicated |
47.3 |
60ppm |
550ppm |
6.3 |
57.1 |
Inferred |
20.8 |
85ppm |
590ppm |
3.8 |
26.9 |
(1) Comparable head grades to similar surficial deposits
operating elsewhere in the world such as Langer Heinrich, which
typically have a mill feed grade of 550-600ppm after beneficiation.
These deposits have not been independently verified by U3O8 Corp.
and information regarding these deposits is drawn from publicly
available information.
Forward-Looking Statements
Certain information in this release are forward-looking
statements with respect to the proposed joint venture and
development plans, economic potential and growth targets of U3O8
Corp's current projects. Forward-looking statements consist of
statements that are not purely historical, including statements
regarding beliefs, plans, expectations or intensions for the
future, and include, but not limited to, statements with respect
to: (a) a joint venture with the Chubut Government, (b) the
low-cost, near-term production goal of Laguna Salada, (c)
compliance with current Chubut mining law, (d) the Laguna Salada
and Berlin PEAs, (e) beneficiation test work on Laguna Salada, (f)
the market opportunities for uranium from Argentina, and (g) the
potential of the Kurupung district in Guyana. Assumptions on which
such statements are based include that: (i) discussions with the
Chubut Government will be favourable, (ii) actual results of our
exploration, resource goals, metallurgical testing, economic
studies and development activities will continue to be positive and
proceed as planned, (iv) requisite regulatory and governmental
approvals will be received on a timely basis on terms acceptable to
U3O8 Corp., and (v) economic, political and industry market
conditions will be favourable. However, such statements are subject
to risks and uncertainties that may cause actual results,
performance or developments to differ materially from those
contained in the statements, including, but not limited to: (1)
that a joint venture will not be formed with the Chubut Government,
(2) timing and outcome of the PEA or that a mine will be achieved
on the Laguna Salada Project in compliance with current Chubut
mining law, (3) risks that a mine will not be achieved on the
Berlin Deposit and other exploration projects, (4) that
beneficiation test work will continue to be favourable and results
from small scale metallurgical testing can be duplicated on a
larger scale, (5) the inherent uncertainties and speculative nature
associated with exploration results, resource estimates, potential
resource growth, future metallurgical test results, changes in
project parameters as plans evolve, (6) volatility of commodity
prices, (7) dependence on regulatory approvals and changes in
legislation, environmental compliance, community support and the
political and economic climate, (8) availability of future
financing, and (9) exploration risk and other factors beyond the
control of U3O8 Corp. including those factors set out in the "Risk
Factors" in our Annual Information Form available on SEDAR at
www.sedar.com. Readers are cautioned that the assumptions used in
the preparation of such information, although considered reasonable
at the time of preparation, may prove to be imprecise and, as such,
undue reliance should not be placed on forward-looking statements.
U3O8 Corp. assumes no obligation to update such information, except
as may be required by law.
To view Figure 1 - Photos of the Soft, Pebbly Nature of
the Laguna Salada Deposit, Argentina, please visit the following
link: http://media3.marketwire.com/docs/uwe926-F1.pdf.
To view Figure 2 - Continuous Surface Mining Scenario
Being Considered for the Laguna Salada Deposit, Argentina, please
visit the following link:
http://media3.marketwire.com/docs/uwe926-F2.pdf.