Peru Copper announces highly favorable column leach results
February 05 2007 - 12:38PM
PR Newswire (US)
VANCOUVER, Feb. 5 /PRNewswire-FirstCall/ -- Peru Copper Inc.
(TSX:PCR / AMEX:CUP / BVL:CUP) ("Peru Copper" or the "Company") is
pleased to announce that it has received highly favorable results
from its recent column leach testing at the Toromocho copper
deposit. The preliminary column leach test results detailed below
suggest that the geology of the Toromocho orebody is particularly
suited to an initial heap leach operation followed several years
later by flotation concentration, which the Company expects could
be built largely from cash flow generated by the heap leach
operation. This could mean a significantly smaller up front capital
investment for the Company, as well as a shorter timeframe to
copper production. The upper 200 to 300 meters of mineralization
contains the highest percentage of chalcocite, a copper mineral
soluble in ferric iron solution, but this zone is relatively low in
molybdenum which increases progressively with depth and becomes an
important by-product below a depth of 200 meters. Neither
molybdenum nor silver will be recovered in the heap leach process
but will be in the flotation concentration operation which follows.
A local source for sufficient low cost sulfuric acid has been
identified which the Company is pursuing for the 50,000 tonnes per
day leaching operation. Also, various arsenic management options
are being evaluated for the small percentage of Toromocho ore which
is affected, including ore segregation, inclusion in heap leach and
evaluation of smelting options, including a possible smelting
destination in Peru which has higher penalty thresholds. As Peru
Copper continues to explore possibilities to optimize the economics
of the Toromocho orebody, it is on track to complete a full
feasibility study by the end of 2007. Additional pre-feasibility
work is also being carried out to evaluate the column leach test
results for the initial heap leach operation and subsequent
flotation plan. Executive Chairman J. David Lowell stated "We are
very encouraged by the results of the ongoing optimization work at
Toromocho of which the positive heap leach results are only one of
many positive studies ongoing. At a time when capital costs to
build a mine are escalating, it is very refreshing to be able to
report to our shareholders that a much lower cost alternative may
be available. Both Gerald Wolfe, our new CEO, and I are very
excited about Peru Copper pursuing the development of this
exceptional copper deposit." Leach Results The results of leaching
28 large diameter columns run on intrusive copper mineralization
have shown higher copper recovery and shorter leaching time than
had been expected. Recovery has generally been in the range of 60%
of total copper. Preliminary results are as follows: Intrusive Rock
Types: --------------------- A 25 tonne sample of intrusive
mineralization was collected from the existing open pit and
prepared for leach at Plenge Labs in Lima. Samples were subjected
to leach ranging from 6", 4", 2" and 1" top crush size. The samples
were subjected to various amounts and rates of acid addition to the
column leaches. The following results have been reported by Plenge
Labs for some selected samples. 1" top size intrusive
mineralization containing 0.33% total copper of which 53.5% was
cyanide soluble copper was subjected to an acid cure and leached in
a ferric sulfate environment for 295 days. The intrusive sample
leached well and 72.9% of the total copper was leached. The sample
consumed 25.7 kg/t sulfuric acid. Non-cyanide soluble appeared to
leach well and the mineralization was still producing copper at the
time the leach was terminated. 4" top size intrusive mineralization
containing 0.33% total copper, of which 53.5% was cyanide soluble
copper, was subjected to a leach using an application rate of leach
solution of 15 L/hr-m2 of 5 gpL H2SO4. The rock was leached for 247
days and yielded 53.5% total copper recovery. An identical sample
crushed to 6" top size is still running and the total copper
recovery has exceeded 60%. The copper is still leaching in the 6"
column. Total acid consumption of the 4" material was 21.9 kg/t.
Bacterial activity oxidizing ferrous iron to ferric iron was noted
in all of the intrusive testing. Blended Skarn and Intrusive Rock
Types: --------------------------------------- Two columns of
blended 1" top size mineralization were run for about 170 days. One
column consisted of a 63% intrusive 37% skarn blend. Leach solution
was introduced at 5L/hr-m2 and 5 gpL H2SO4. The blended sample did
not exhibit percolation problems as noted in the 100% skarn
columns. The blended mineralization assayed 0.43% copper of which
42.7% was cyanide soluble. In 170 days the column yielded 53.1%
copper extraction and 14.26 kg/t sulfuric acid consumption.
Although the acid consumption appears to be low it was necessary to
add ferric sulfate to the system, increasing the actual acid
addition to the column. The second column had similar results to
the first column. High Arsenic Rock Types: ------------------------
Two columns were run on drill core composites representing high
arsenic material that will be diverted to heap leach to avoid
smelter arsenic penalties. This material was crushed to 3/4" top
size and leached in 4" columns at a leach solution application rate
of 15 L/hr-m2. The mineralization was leached for about 175 days.
The samples contained 0.446% and 0.349% total copper of which about
73.5% was cyanide soluble. After 175 days of leaching the
respective copper recoveries were 64.9% and 72.9% with 21.4 kg/t
and 17.96 kg/t gross acid consumption. Both columns were producing
their own acid by the time the leaches were terminated and both are
still responding to the ferric sulfate leach solution. J. David
Lowell, Registered Professional Engineer, Arizona State Board of
Technical Registration and Executive Chairman of the Company, who
is the Qualified Person for the project. Mr. Lowell has reviewed
and approved the contents of this news release. Cautionary Note to
U.S. Investors - The United States Securities and Exchange
Commission permits U.S. mining companies, in their filings with the
SEC, to disclose only those mineral deposits that a company can
economically and legally extract or produce. We use certain terms
in this press release, such as "mineral deposit", that the SEC
guidelines strictly prohibit U.S. registered companies from
including in their filings with the SEC. U.S. Investors are urged
to consider closely the disclosure in our Form F-3 Registration
Statement, File # 333-121527, which may be secured from us, or from
the SEC's website at http://www.sec.gov/edgar.shtml.
Forward-Looking Statements: Statements in this release that are
forward-looking statements are subject to various risks and
uncertainties concerning the specific factors identified in the
Peru Copper Inc. periodic filings with Canadian Securities
Regulators. Such forward-looking information represents
management's best judgment based on information currently
available. No forward-looking statement can be guaranteed and
actual future results may vary materially. Peru Copper does not
assume the obligation to update any forward-looking statement. Safe
Harbor Statement under the United States Private Securities
Litigation Reform Act of 1995: Except for the statements of
historical fact contained herein, the information presented
constitutes "forward-looking statements" within the meaning of the
Private Securities Litigation Reform Act of 1995. Such
forward-looking statements, include but are not limited to
statements with respect to estimated capital costs, cash flow from
potential heap leach operations and timing and amount of actual
copper recovery, Often, but not always, forward-looking statements
can be identified by the use of words such as "plans", "expects",
"is expected", "estimates" or variations (including negative
variations) or such words and phrases, or state that certain
actions, events or results "may", "could", "would", "might" or
"will" be taken, occur or be achieved. Forward-looking statements
involve known and unknown risks, uncertainties and other factors
which may cause the actual results, performance or achievement of
Peru Copper and/or its subsidiaries to be materially different from
any future results, performance or achievements expressed or
implied by such forward-looking statements. Such factors include,
among others, risks related to the final results of current testing
and studies at Toromocho, exploration and potential development of
Toromocho, risks related to international operations, risks related
to the timing and amount of future production, changes in project
parameters as plans continue to be refined, future prices of
copper, silver, molybdenum and gold, possible variations of ore
grade or recovery rates and other risks of the mining industry, as
well as those factors discussed in the section entitled "Risk
Factors" in the Form F-3 as on file with the Securities and
Exchange Commission in Washington, D.C. Although Peru Copper Inc.
has attempted to identify important factors that could cause actual
results to differ materially, there may be other factors that cause
results not to be as anticipated, estimated or intended. There can
be no assurance that such statements will prove to be accurate as
actual results and future events could differ materially from those
anticipated in such statements. Accordingly, readers should not
place undue reliance on forward-looking statements. CONTACT: please
contact Patrick De Witt, Director of Investor Relations at (604)
689-0234 or DATASOURCE: Peru Copper Inc. CONTACT: please contact
Patrick De Witt, Director of Investor Relations at (604) 689-0234
or
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