GOLD EXTRACTION_proof 19/07/2016 14:53 Page 2
GOLD EXTRACTION
range of temperatures over a span of horizontal
distances.
UHSB surface trials to pump the special
backfill at a product temperature ranging
between 30 and 35°C over a 1,000 m distance
were successful.
In addition, an acoustic monitoring system
has been installed to monitor the rock mass
response during drilling. “Basically,” explains
Jacqueline Storbeck, Project Lead Engineering ,
Technology & Projects, “we measure the UHSB
response in the rock while drilling to ensure that
the rock conditions remain constant (the
product is as hard as the rock thus filling the
hole we try to keep the conditions constant).”
“As part of the ongoing process to install
instrumentation to continuously measure the rock
conditions, a software data logging system was
installed in the prototype sites. We now log all
information from the acoustic monitoring system.”
Laser mining
Particularly interesting for narrow vein mining –
gold being a prime prospect – Merger Mines
Corp says using “lasers for spalling (breaking)
rock underground or to drill blastholes in open
pits, will eliminate conventional methods of
drilling and blasting.” Preliminary estimates
indicate substantial savings can be realised in
time, material costs, and operating costs.
“This new mining method involves the use of
high optical power output lasers to cut or spall
ore bearing material from the host rock.
Because the spalled material is in the form of
‘pea’ sized chips, these chips can easily be
moved from the working face to the surface. A
milling advantage is that these
small chips do not require crushing
and can be discharged directly to
the ball mill or leach pad.”
Merger Mines is developing a
single head laser mining device for
use in underground mines. Initially,
this single head laser mining unit will be used
for narrow high grade veins. The mining width
for this unit will be about 60 cm. Once the
operating parameters of the single head mining
unit are established, multi-head laser mining
units can be developed for stopes wider than
this. For example, a four unit laser mining array
would work in a 2.4 m wide drift. Initially only
the ore bearing material is removed, and then
the waste is removed on a second pass with the
unit.
With experience gained from the mining
program, laser mining heads will be mounted on
mobile equipment and used for driving drifts
and development headings. Plans are also in
place for driving raises, either unlined or
timbered. Not presently under consideration,
but certainly not ruled out, Merger Mines says,
is the sinking of shafts.
Underground, “lasers will reduce operating
costs substantially as jacklegs, drill steel, bits,
powder, blasting caps and a multitude of small
tools will be eliminated from normal stoping
costs. Labour costs for mining and material
costs will be greatly reduced. Underground
supervision will be simplified and overall mine
safety should improve. Plans are in place to
design a laser mining unit where a one or two
person crew could operate multiple working
faces from a central control module.”
Merger Mines also believes that “in theory,
mining without blasting could reduce or
eliminate rock bursts.”
In open pit mining, a laser mining head could
be readily mounted on a standard track drill and
be used for blasthole drilling.
The head has the capability to chamber, or
enlarge the bottom of the drill hole for shaped
charges for special blasting requirements.
Çöpler Sulphide
Amec Foster Wheeler has been awarded a
reimbursable EPCM contract by Anagold
Madencilik for the Çöpler Sulphide Expansion
Project to expand and extend the life of the
Çöpler gold mine (Alacer Gold) in the Çöpler
District, Erzincan Province, Turkey. Amec Foster
Wheeler’s scope of work will include detailed
engineering, procurement, construction
management services and support during
commissioning and performance testing. The
Çöpler Sulphide Expansion Project is due for
mechanical completion in the second quarter of
2018 and will commence production the third
quarter of 2018.
This award follows Amec Foster Wheeler’s
prior completion of basic engineering and
procurement activities.
Roberto Penno, Amec Foster Wheeler Group
President for Asia, Middle East, Africa and
Southern Europe: “The award of this contract
confirms our capability and experience in
delivering worldclass gold projects, and
demonstrates our ability to combine our
technical expertise from across the globe with
our significant in-country presence. We look
forward to continuing our growing partnership
with Anagold Madencilik on this important
project for the Turkish mining industry.”
The objective of the Çöpler Sulphide
Expansion Project is to enable the facility to
process 5,000 t/d of sulphide ore, in addition to
the existing heap leach processing of oxide ore,
and to extend the life-of-mine to more than 20
years, with remaining gold production of 4.0
Moz.
Alacer Gold is a leading low-cost gold
producer, with an 80% interest in the world
class Çöpler gold mine in Turkey. During 2016,
Çöpler is forecast to produce 150,000 to 170,000
oz at total cash costs of $575 to $625/oz.
Çöpler’s oxide ore is currently being processed
in a conventional crush, agglomeration, heapleach and gold recovery circuit.
Çöpler Sulphide Expansion Project - unit cost
metrics (life-of-mine average):
n Mining - $1.50/t mined
n Rehandle - $1.12/t rehandled
n Heap leach processing- $8.09/t processed
n POX processing - $31.8/t POX processed
n Site support costs- $5.83/t processed
Costs per ounce (life-of-mine average, $/oz):
n Cash operating costs (C1)
563
n Byproduct credits
9
n Cash operating costs net of byproducts (C1)
554
n Royalties
17
68 International Mining | AUGUST 2016