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MODERN MINING
January 2017
Top projects
TIN
plant, a tailings dam and associated facilities
with a ROM process capacity of 360 kt/a. It esti-
mates the project’s ungeared NPV
8
(real after
tax) at US$262,7 million and the ungeared IRR
(real after tax) at 48,4 %. The payback period
from first tin production is put at 23 months.
The mine would produce 10 750 tonnes of
tin in concentrate on average per year (account-
ing for approximately 3 % of world production)
over an almost 12-year mine life, with cash
costs being US$7 396 per tonne tin.
DRA are running a Front End Engineering
and Design programme to optimise the designs
and processes of Bisie. The results of this pro-
gramme will be available early in 2017.
The proposed mining method is Sub Level
Caving (SLC) to remove the orebody in retreat
fashion from the southern and northern limits
of mineralisation back towards the centralised
trucking ramp. Blasted ore will be loaded by
14-tonne capacity rubber-tyred LHDs dump-
ing into 40-tonne articulated dump trucks and
hauled to surface where it will be stockpiled
ahead of processing for tin recovery.
The process design is based on recovery
of tin into concentrate through conventional
– and simple – gravity separation methods.
Mined ore will be crushed to 100 % passing
10 mm. The coarse material (10 mm to +1 mm)
accounts for 75 % of the mass flow and the tin
contained in this size fraction will be recov-
ered in conventional jigs. The fine material
(-1 mm) makes up the balance of the mate-
rial and the tin contained in this stream will
be recovered using spirals. The concentrates
from both the jigs and spirals will be milled
and subjected to flotation to remove sulphide
material. The tin rich concentrate will be
thickened, filtered and dispatched for trans-
port to smelters for further refining.
Comments Kamstra: “Our present plan is to
truck the concentrate to a secure export ware-
house – a tin terminal, if you like – in Goma
using rough terrain vehicles. Once in Goma,
it will be sold to tin traders. Our concentrate
will grade at more than 60 % tin and will be
unique inasmuch as it will contain no penalty
elements such as bismuth or arsenic.”
At this stage, Kamstra envisages that con-
struction of Bisie – which will take place over
18 months – will start in 2017, which will mean
first production can be expected by 2019. To
build the mine, Alphamin has appointed DRA
– responsible for building the process plant
and other infrastructure at the Kibali gold mine
in the north-east of the DRC – as its preferred
EPCM contractor.
In anticipation of the start of construction,
there is currently a 60 m return airway adit
being developed at the site. Kamstra describes
this as an exercise in “getting some infrastruc-
ture in and getting an understanding of the
rock” while, at the same time, gauging the avail-
ability and level of mining skills in the area.
To take Bisie into implementation, Alpha
min has put together what it believes is a highly
experienced team. Kamstra himself is a civil
engineer who started his career with Grinaker
while the company’s COO is Trevor Farber,
who played a major role in developing the
Blue Ridge platinum project in South Africa
and the Kinsenda copper project in the DRC.
Miners working on the
return airway drive have
all been recruited from the
local community.
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