June 2014
MODERN MINING
7
MINING News
Robert Friedland, Executive Chairman of Ivanhoe
Mines, and Lars-Eric Johansson, Chief Executive
Officer, have issued a summary of significant,
ongoing exploration and development activi-
ties at the company’s Kamoa copper discovery,
located near the mining centre of Kolwezi in the
DRC’s southern province of Katanga.
Friedland said the work has further confirmed
that the focus of the company’s initial mine devel-
opment at Kamoa will be on the high-grade
Kansoko Sud area, where ongoing infill drilling
since the last resource estimate was produced
in 2012 has defined a thick, near-surface zone of
high-grade copper sulphide mineralisation that
would be amenable to treatment by a conven-
tional copper flotation plant.
One of the 101 infill holes drilled in this area,
for which assays were received in April 2014, inter-
cepted 15,7 m (true width) of 7,04 % copper at a
1,5 % total copper cut-off.
Since issuing an updated, independent pre-
liminary economic assessment (PEA) for the
Kamoa project in November 2013, Ivanhoe has
concentrated its exploration drilling activities
on the acquisition of samples for metallurgical
testing, as well as undertaking drilling on 200-m
close-spaced sections in the Kansoko Sud area.
Exploration drilling has been directed at infilling
those areas identified as primary mining targets
in the PEA.
A total of 60 of the 101 holes with assays
returned since the release of the updated PEA
six months ago were drilled in the Kansoko Sud
area, 29 were in Kansoko Centrale, one in Kansoko
Nord, nine in Kamoa Sud and two in Makalu.
Infill drilling of the initial mining area has
confirmed the overall grade and thickness of the
December 2012 resource estimate in these areas
and has provided invaluable refinement within
localised areas. While traditionally modelled on
a 1 % total copper cut-off to define a selective
mineralised zone, the deposit has shown that
grade continuity also exists at an elevated 1,5 %
total copper vertical cut-off and that a 2,0 %
vertical total copper cut-off may be feasible in
certain areas.
Recent work defining the selective mineralised
zone (SMZ) at higher vertical cut-offs has shown
that narrower, higher-grade intervals create
more expansive, contiguous zones, which should
improve initial mine economics.
A new base case for future engineering stud-
ies is being developed using a 1,5 % total copper
cut-off with a minimum 3-m mining height and a
maximum mining constraint of 6 m (a single min-
ing cut); incremental mineralisation above 6 mwill
be included only if the grade of the incremental
mineralisation exceeds 2 %. This approach was
introduced for thicker intercepts to ensure ini-
tial mining cuts would extract only higher-grade
material.
The initial mine plan produced in the PEA
focused initial mining in the shallower portion of
Kansoko Sud, an area previously drilled on 400-m
spacings. Since completion of the PEA, Ivanhoe
has concentrated on substantially closing the
distances to 100-m spacings on 200-m-spaced,
east-west lines, with the goal of demonstrating
grade and structural continuity of this high-grade
zone at potentially elevated cut-offs. Drilling
is continuing in this area; results to date are
extremely encouraging and have confirmed – and
in some locations exceeded – the initial results
based on holes spaced 400 m apart.
During the remainder of 2014, Ivanhoe intends
to continue its detailed infill programme in the ini-
tial mining area to cover an area of approximately
one square kilometre with a 100-m detailed grid.
In line with the phased approach to proj-
ect development outlined in the 2013 updated
Kamoa PEA, the Kamoa pre-feasibility study (PFS)
is progressing on the basis of an initial 3 Mt/a
mine and concentrator.
Preparations are underway to start the first
mine-access decline at Kamoa’s Kansoko Sud area.
The decline is designed to provide access to the
high-grade copper resources that would be tar-
geted for the planned first phase of production
using the room-and-pillar mining method.
Kamoa is considered amenable to large-scale,
mechanised mining using a combination of
room-and-pillar and drift-and-fill methods, given
the deposit’s favourable mining characteristics as
derived from the December 2012mineral resource
– including its relatively undeformed, continuous
mineralisation, local continuity between closely-
spaced drill holes and flat-to-moderate dips.
In December 2012, a new, independent min-
eral resource estimate was prepared for the
Kamoa copper discovery by AMEC E&C Services,
of Reno, Nevada. The new estimate ranked Kamoa
as Africa’s largest, high-grade copper discovery
and the world’s largest, undeveloped high-grade
copper discovery.
As of January 2013, Ivanhoe Mines had dis-
covered indicated mineral resources of 739 Mt
grading 2,67 % copper, containing 43,5 billion
pounds of copper, and inferred mineral resources
of 227 Mt grading 1,96 % copper, containing 9,8
billion pounds of copper. A 1 % copper cut-off
grade and a minimum vertical mining thickness
of 3 m were applied in each classification.
Ivanhoe provides update on Kamoa discovery
