TIDMFML
RNS Number : 0203O
Frontier Mining Ltd
16 September 2013
FRONTIER MINING LTD
("Frontier" or "the Company")
Operations Update - Publication of Newsletter
Frontier Mining (AIM:FML), the AIM listed exploration,
development and production Company focused on Kazakhstan, is
pleased to announce the publication of the September 2013
newsletter which contains the following report from Adam Moroney,
an independent degree-qualified consultant with 20 years of SX/EW
management and heap leach research experience.
The report from Adam Mooney is set out below and the newsletter
can be found on the Company's website: www.frontiermining.kz
"Introduction
I was engaged by KazCopper in May 2013 as Benkala's first
Expatriate Consultant to assist in heap leach and SX/EW operations.
I have 20 years' experience in copper, nickel and cobalt
hydrometallurgy in the areas of mine production, mine-site
management, process plant commissioning and process
research/development. One of my areas of expertise is in heap leach
development and management. I have led processing plants in
achieving record Life of Mine annual production and have authored
five patents; four of which are in the technically-challenging
field of nickel laterite heap leaching.
Of the thirteen heap leaching operations and projects I have led
or been involved in, every case has been technically different due
to the distinctive physical and chemical nature of the ores at the
different sites. The localities I refer to include Australia, Peru,
Chile, Turkey, Philippines, Colombia, Indonesia and now Kazakhstan.
Each site has also had its own unique combination of cultural,
climatic, geographical, infrastructure, and political
challenges.
The strengths and opportunities that can be exploited at the
Benkala Operations are its large resource, low acid-consuming ore,
readily-available and developed utilities and competing
raw-materials suppliers. Like any mining business at an early
stage, cash flow is always a challenge we will have to overcome,
along with issues such as the clayey nature of the ore, extreme
winter-time conditions, unproven equipment reliability (excluding
SX/EW), high employee turnover and geographical remoteness.
Full-scale production trials for increased copper production
rate
From a technical perspective, one of the greatest challenges, as
previously mentioned, is the clayey nature of the ore. The shallow
oxide ore and underlying secondary sulphide ore both contain
significant amounts of kaolinite clays. The copper minerals are
more suited to heap leach extraction of copper rather than
pyrometallurgical extraction, but the clays represent the
challenge. Of all of the heap leach properties I have been involved
in, Benkala has the highest clay content. The clay prevents
gravity-led percolation of the extracting liquid through the heaps,
causing a significant bottleneck in the process.
Fortunately, the clay content of the Benkala reserves decreases
gradually with depth, as the secondary sulphides are exposed and
mined. The first recommendation I made was to undertake block-wise
"permeability grade control" at the pit, in the same manner as is
conventionally done for copper grade control. The crux of the plan
is to control permeability at the leach heaps rather than to
control copper grade at the leach heaps. This plan is sound
because, without permeability control, copper production would
remain well below our internal target.
Upon implementing permeability grade control on June 6, the next
2.5 metre heap at Pad 3 exhibited significantly improved
permeability, and a decision was made on July 3 to increase the
heap height to 3.5 metres. Each time the heap height is
increased:
-- leach pad capex and opex decreases proportionally with respect to tonnes of ore stacked
-- stacking plant availability increases significantly, and
-- SX/EW opex decreases with respect to tonnes of cathode produced.
Permeability was not affected at the 3.5 metre section and a
decision was made on August 9 to increase stack height to 4.2
metres; the maximum allowable with the existing stacking equipment.
Permeability of the stacked ore was further improved on August 13
by testing and implementing a new method of agglomerate moisture
control during production trials.
I requested on August 14 that the radial stacker be upgraded to
enable up to 8 metre stack height. The request for 8 meters was
based on promising news arising from research-style laboratory
agglomeration test work. Unfortunately, the existing radial stacker
can only be modified to reach a maximum of 6 meters.
With low permeability issues now behind us, it is possible to
employ the conventional forced-aeration method of oxidation for the
secondary sulphide minerals that are being stacked. Forced-aeration
supplies oxygen to the heap, allowing, through a moderately complex
chain of chemical and biological processes, greater rates of copper
extraction from the sulphide minerals. The forced-aeration concept
was presented to Frontier Mining during my first visit in May,
however it could not be implemented until permeability was
improved; a relatively permeable heap is required to allow ingress
of air.
So until forced-aeration is successfully implemented, the rate
of copper extraction from the new secondary sulphide heap at Pad 3
is expected to remain lower than that of typical oxide heaps. The
copper is not lost from production, it is just delayed. Once
forced-aeration is implemented into new leach heaps, the ferric
iron generated from them will not only increase the rate of copper
extraction from the aerated heap, but will also increase the copper
extraction rate from the older non-aerated heaps. This is because
ferric iron is the penultimate product of forced-aeration, and it
is ferric iron that extracts the copper from the secondary
sulphide.
Research and development for robust stack height increases and
effective forced aeration
Laboratory-scale research of agglomerate additives commenced in
parallel with the production trials. Five material-types were
identified as potential low-cost options for robust permeability
improvement. To date, one of these material-types have been
identified as superior, two as potentially useful, one as too
expensive, and one as ineffective. The superior material has the
following attributes:
-- Produces robustly permeable agglomerates, even from the most clayey Benkala ores,
-- Retains high agglomerate permeability under loads equivalent to >10 meter stack height,
-- Compatible with downstream SX/EW unit operations,
-- Locally available,
-- Low-cost,
-- Patentable.
The dose rate and dosing technique of the material have been
partly optimized for the most clayey ores and process optimization
continues for less clayey ores, where it is anticipated that lesser
quantities of the material will be required. Although an ideal
material has already been identified, alternatives continue to be
investigated at Benkala. The identity of the material will not be
publically announced until IP protection is in place.
Other Improvement Projects
As stated earlier, the Benkala Operation, like any other mine,
has its numerous weaknesses and threats. Each of these need to be
planned for, budgeted for, and managed in a forward-thinking and
intelligent way. Apart from the clay issue described above, the
other great weakness forced upon Benkala is the harshness of
wintertime. The focus on this problem is equally intense, however
it is likely that the first achievements in this area will be to
operate further into the winter period, and to recommence
operations earlier in the subsequent year. Other improvement
projects center upon the need for capital investment in order to
remove existing bottlenecks in the production process.
I look forward to working with Frontier going forward.
Adam Moroney, BAppSc
Consultant of Cu Ni Co hydrometallurgy"
For further details please contact:
Frontier Mining
Ltd Yerlan Minavar +44 (0) 20 7898 9019
Libertas Capital Sandy Jamieson
(NOMAD) Richard Morrison +44 (0) 20 3697 9495
RFC Ambrian (Broker) John Harrison +44 (0) 20 3440 6800
Walbrook PR Guy McDougall
(Media Enquiries) Lianne Cawthorne +44 (0) 20 7933 8780
Walbrook IR Paul Cornelius
(Investor Enquiries)
-END-
This information is provided by RNS
The company news service from the London Stock Exchange
END
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