FM-t...in the news:
First Quantum updates Bwana project in Zambia
Wed 27 Feb 2002
News Release
Mr. Sean Whittome of Bwana Mkubwa Mining reports
First Quantum Minerals has disclosed that its Bwana Mkubwa project was the
first significant investment by a private company in Zambia's mining
industry following the election of President Chiluba in 1991. Bwana Mkubwa
Mining Ltd. (BMML) is a wholly owned subsidiary of First Quantum. The
original project, established in just 11 months, is leaching copper oxides
from the tailings of ZCCM's old Bwana Mkubwa open pit (shut down in 1984),
about six kilometres outside Ndola. BMML established an SX-EW plant and an
acid plant, both built by Genrec, with operations starting up in 1998 with
a planned five-year life based on reserves of 92 tonnes at 0.78 per cent
copper. However, the life of the Bwana Mkubwa operation has now been
significantly increased through the new Lonshi mine just across the border,
three kilometres into the Katanga province of the Democratic Republic of
Congo (DRC). This will allow copper production to be raised to 30,000 to
40,000 tons per year, with a mine life of five to 10 years.
Or maybe Bwana will become an even bigger operation. In October, FQM
announced a 390-per-cent increase in the copper resource at its effective
85-per-cent-owned Lonshi deposit. The open pit resource has grown from
60,000 to 295,000 tons of contained copper. Based upon the substantial
Lonshi resource upgrade, an expansion of the SX/EW facilities at Bwana
Mkubwa to a production capacity of 30,000 tons per year of London Metal
Exchange grade copper cathode is being considered. Construction would take
approximately 12 months to complete.
As of Oct. 1, 2001, the Lonshi resource stands at 2,391,767 tons grading
46.73 per cent copper (160,915 tons of contained copper) measured. The
indicated resource is 2,739,767 tons grading 4.89 per cent copper for
133,975 tons contained and the total is 5,131,483 tons grading 5.75 per
cent copper for 294,890 tons contained. The mineralization is hosted within
an average 15-metre-thick package of weathered Roan clastics and distal
units which outcrop on surface and dip to the east at 38 degrees. The
deposit remains open along strike and to depth. The initial drill program
established an oxide copper open pit resource of approximately one tonne
grading 6 per cent copper or 60,000 tons of copper. A second phase resource
definition drilling program totalling 6,441 metres (including sterilization
drilling) has been completed along a strike length of 800 metres and to an
average depth of 65 metres. The resource is based upon the results of 5,747
metres of drilling in 138 drill holes (91 reverse circulation, 10 diamond
core and 37 air core) using a 2-per-cent-copper cutoff grade. Metallurgical
testing on Lonshi ores indicates that they are highly amenable to direct
acid leaching and demonstrate a recovery rate of approximately 86 per cent.
Assays were carried out by BMML with appropriate quality control
procedures. Composite samples were checked by Independent Metallurgical
Laboratories (IML) and Analabs in Perth, Western Australia, where the
sampling precision and accuracy between IML, Analabs and BMML results were
determined to be excellent.
As the tailings retreatment project that it started life as, Bwana's
capacity was about 10,000 tons per year of copper. However, knowing the
shortage of acid on the copper belt, FQM had Signet Engineering design the
acid plant with an annual capacity of 110,000 tons (320 tons per day),
which was about three times the project's own requirements, allowing it to
supply other customers. Thanks to these external acid sales Bwana is a very
low-cost copper producer, averaging 11 cents per pound of copper, net of
credits, during 2000. Even without acid credits, its current cash cost is
around 35 cents per pound.
Tailings are reclaimed from No. 4 tailings. Dump using high-pressure
hydraulic monitoring and the slurry is pumped to the acid leaching plant.
The tailings are processed by standard agitated leaching in dilute
sulphuric acid to dissolve copper, with the subsequent recover of the
dissolved copper using SX-EW technology.
Taking advantage of the huge market for sulphuric acid on the copper belt
and the fact that Zambian resources cannot supply all the demand, BMML has
also now purchased a used acid plant from South Africa. It re-engineered
the "front end" of this plant to make it very similar to its original
sulphur burning plant. This second plant was set up in just five months and
has added another 40,000 tons per year to bring BMML's total acid available
for sale to 110,000 tons per year, along with the 40,000 tons per year it
uses in its own SX/EW plant.
Additional resources
Soon after it was established, BMML undertook exploration in the vicinity
of its plant with a view to develop further oxide reserves. When this
exploration identified minimal resources, the company embarked on a wider
search. The Lonshi prospect had been subject to some cursory exploration
approximately 70 years ago, but this did not result in a mine development.
BMML learned of it though researching archive material and subsequent
exploration confirmed its viability.
Lonshi lies 30 kilometres southeast of the Bwana plant, adjacent to the
Lonshi River. The topography is wetlands at a level near the water table,
hilly terrain and indigenous forest. The sparse, indigent population of
this totally rural area survives on subsistence farming. The Lonshi deposit
occurs within the upper units of the Lufilian arc. Most of the Zambian
copper belt deposits are found within the lower part of the Lufilian arc,
whereas most of the DRC deposits are found in the upper units, and tend to
be richer.
Sean Whittome, general manager of BMML, explains that, "The Lonshi mine
development has cemented Bwana's Mkubwa's expansion aspirations." The
current retreatment process had a finite life of only about 24 months left
by mid-2001. The rich oxide Lonshi deposits, suitable for treatment at the
Bwana plant, require little overburden removal. "We are currently achieving
a stripping ratio of 26 to 1," Mr. Whittome explains. The Bwana plant has
been upgraded to treat the Lonshi ore with the installation of crusher, a
5,000-ton stockpile, a SAG mill and a filter system, all bought as used
equipment in South Africa at a capital expenditure of some $4-million. This
front end to the SX-EW plant was also designed by Signet. The Bwana plant
now has the capacity to produce up to 35,000 tons per year. "This will also
provide additional capacity for us to treat other resources, such as
low-grade dumps in the area," Mr. Whittome says.
Phase 1 of the Lonshi development, carried out in co-operation with the
DRC's ministry of mines in Kinshasa, has involved a capital expenditure in
the region of $3-million. It comprises the extraction of Lonshi ore, its
transportation to the Bwana Mkubwa plant and processing there. The project
is thought to be only the second mining operation in the world in which
agreement has been reached for ore to be mined in one country and taken
across the border to a neighbouring country to be processed. The only other
known mining agreement of this kind is on the Chile/Argentina border
(Barrick Gold's Pascua-Lama project), where production has yet to begin.
Bwana Mkubwa Mining Congo (BMMC) controls the mining at Lonshi and BMML
processes the ore.
Mr. Whittome says that the authorities in both Zambia and DRC have been
very co-operative in the development of Lonshi. He explains that the latter
were "very keen to see this project go."
However, as the tailings at Bwana run out, the operation will need
additional lower grade feed to blend with the high-grade Lonshi ore.
Besides some further low-grade dump material at Bwana, BMML now has
extensive prospective ground in the DRC. Its mining convention covers all
the land south of 13 degrees south across the "Pedicle," the part of the
DRC bordered on three sides by Zambia. BMML also holds the exploration
rights to all known copper deposits in the Pedicle south of Mokambo,
opposite Mufulira in Zambia.
Further into the project, there is a plan for more exploration drilling to
determine the extent of sulphide ores at Lonshi and to ascertain the
feasibility of building a concentrator. The orebody remains open on dip and
to the north and south. Construction of a concentrator there, if it were
determined to be viable, would require the construction of substantial
infrastructure, such as an electricity supply.
Mining in the Lonshi open pit will probably extend to 100 metres in depth.
The first campaign, last year before it rains, extracted the ore to be
treated this year. Mining went down to 35 metres and produced ore with a
head grade of 5.84 per cent copper. Below 100 metres, consideration will be
given to developing an underground operation should there prove to be
sufficient ore at depth. Production from the oxide ores, processed at
Bwana's SX-EW plant, is expected to be about 25,000 tons per year of
copper, in addition to the 10,000 tons yielded by retreating tailings. If
the sulphide ores are viable, output could rise to 50,000 tons per year.
Lonshi has been an extremely "fast-track" development. Drilling of the
deposit only began in November, 2000, and finished in June, 2001.
Excavation of the pit, bush clearance and infrastructure work such as the
construction of haul roads, started when contractor Congolese Construction
& Mining (CCM), wholly owned by South African contractor MCC, moved on site
in early July. It then became a race against time to make as much progress
as possible before the beginning of the rainy season. This operation moved
11 million square metres of material, including 600,000 tons of ore, by
mid-December when the rains started to reach their peak. No further mining
will take place until the rains ease in mid-February.
CCM's contract involves the development and operation of the mine, the
construction of the haul road from the mine to an ore stockpile,
established on the Zambian side of the border, and the haulage of ore to
that 500,000-ton stockpile. BMML undertakes all the mine planning,
geological control and surveying. An independent haulage contractor
transports the ore from the stockpile to the Bwana plant. The total cost of
mining and hauling Lonshi ore to the plant will be approximately
$11-trillion.
BMML has established a new road on higher, and therefore drier, ground to
allow ore haulage from the Lonshi stockpile to Bwana to carry on during the
rainy season. This will then allow year-round mining and make the CCM
contract simpler as its equipment and operators can then be employed at
Lonshi year-round.
ADT haulage
Ore was first found at a depth of just two metres, and only some 157,000
square metres of overburden was removed before striking the ore. This is a
free digging operation, requiring no drilling and blasting. However, large
quantities of water are encountered. There is a substantial pumping
capacity to handle this and 1,000 gum trees are being planted to absorb the
water in the longer term.
CCM's earthmoving fleet consists of 19 articulated dump trucks (ADTs). Most
are Bell B40s, a mixture of the new D-Series units, some B40CMs and B40Bs.
These are used on the long ore haul, about 30 kilometres from the top of
the pit ramp, to the stockpile. Most of this haul, with the exception of
the ramps out of the pit, at gradients of around 10 per cent, is on flat
dirt roads. Three Caterpillar D400E ADTs haul overburden 300 metres to the
waste dump. There are three 90-ton O&K hydraulic excavators (one RH30E and
two RH30Fs), a Caterpillar D9 dozer, a grader, and a Bell 36,000-litre
capacity B40 water tanker. CCM originally employed trained Zambian
operators, but the contract stipulated that the company employ Congolese
operators and train them. These operators have now started work and are
performing well. There are three operations teams on each 10-hour shift,
with each team consisting of an excavator and five ADTs. The target for
each team is 100,000 square metres a month and the contract, which awarded
to CCM on open tender, is for a total of 12 million square metres (bank).
CCM's site manager, Sean Stirling, says use of the plant fleet is close to
100 per cent. He also noted that during MM's visit, before the rainy season
began, that he anticipates: "When the wet conditions set in, the Bell ADTs
with their excellent traction and gradeability, will play a key role in
coping with heavy underfoot conditions. The Bell trucks are ideally suited
for this application, and are providing an average mechanical availability
of close to 100 per cent." There is one Bell maintenance technician
permanently assigned to the Lonshi ADTs.
A substantial element of civil work was carried during the early
development of the mine excavation. Spoil and overburden was used to build
a 25-metre-wide, 300-metre-long dam wall over a swampy tract of land, and a
750-metre-long canal has been excavated to divert the course of the Lonshi
River.
The Lonshi ore stockpile compromises a base of lower grade ore. There are
two ore types at Lonshi -- terre noire (literally translated from French as
black earth), that tends to be higher grade, and Lonshi conglomerate. As
the orebody plunges then flattens, there is more terre noire. To allow the
Bell ADTs to run on it the lower grade stockpile base is graded using a
Wright G66 grader. The Caterpillar D9 dozer also works on the stockpile. A
Caterpillar 966 wheel loader loads the ore onto the highway trucks that
haul it to Bwana.
Considerable attention has been paid to environmental planning. A permanent
wetland has been created at Lonshi and fish will be introduced to the dam
(largely to supplement the diet of the local people). "The project has been
structured to ensure that it will have minimal impact on the area's flora
and fauna," says Mr. Stirling. The dam would also supply water for
irrigation schemes to allow year-round crop harvesting by the local
population. |
