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August 2015
MODERN MINING
25
RUBIES
Gemfields’
Montepuez ruby mine
Gemstones are currently
mined from a series of
shallow open pits. There are
two main operating areas –
Mugloto and Maninge Nice.
“This, together with various expansion
opportunities that are already at hand, and
the impact that our continued global market-
ing and promotional initiatives are expected to
generate, deliver a high level of confidence in
Gemfields’ ongoing efforts to reinvigorate the
global coloured gemstone market place. As I
have said on many occasions over the past few
years, this is still just the very beginning, with
much more yet to come. I would also like to
thank Mwiriti and the Mozambican govern-
ment for their continued support.”
Discovered in 2009 and located in the
north-east of Mozambique in Cabo Delgado
Province approximately 170 km west of Pemba,
Montepuez is said to be the world’s largest ruby
and conundrum deposit. Gemfields acquired
its 75 %-stake in 2011 from Mwiriti Lda for a
total consideration of US$2,5 million and the
acquisition was completed in February 2012.
Montepuez Ruby Mining Lda (MRM) is the
project operator and represents a joint venture
between Gemfields and Mwiriti.
Although still in the bulk sampling phase,
Montepuez is already a fairly substantial
operation, with 369 employees (including 51
expatriates), 248 contract security personnel,
as well as additional civil and drilling contract
employees. There is a semi-mobile 100 t/h
wash plant, complete with jigs, on site plus a
sorting house while the Gemfields-operated
mining fleet consists of six excavators, 17 ADTs
and 18 tipper trucks. A 10 km long powerline
connects the site to Mozambique’s national grid
but backup generators are also available. Water
(potable and process) is sourced from seven
boreholes.
Gemstones are currently mined from a series
of shallow open pits. Some 45 % of the total
production is being sourced from the Maninge
Nice pit, a primary amphibolite deposit that
extends up to 28 m below surface, with the
balance coming from the Mugloto pits, which
extract secondary gravel deposits originating
from ancient river channels. Most of the mate-
rial is free dig with some of the harder laterite
needing to be ripped by a bulldozer.
Bulk sampling operations started in August
2012 and have continued to scale up progres-
sively, producing consistently encouraging
results, says Gemfields. As of July this year,