American Bonanza Provides Copperstone Gold Mine Progress for December
VANCOUVER, BRITISH COLUMBIA -- (Marketwire) -- 01/17/13 -- American
Bonanza Gold Corp. (TSX:BZA)(OTCQX:ABGFF) ("Bonanza" or "Company") is
pleased to announce that the 100% owned Copperstone gold mine in
Arizona continued to make significant progress during December.
During December, Copperstone recovered more ounces of gold into
concentrate than in any previous month, and maintained production
from the underground mine and the development mining. The Company is
encouraged with the recent progress as it continues towards its goal
of achieving commercial production, estimated for the first quarter
During December, ore was available for mining in five zones, which is
similar to performance during November. This is a significant
achievement towards bringing mine output to design levels of 450 tons
per day of ore. The five zones are developed, with access, power
distribution, and water management being maintained as development
mining continues to advance.
The main objective for the development mining program is now to
provide access to two additional zones over the next month. This will
provide ore available for mining subsequent to the zones which are
currently being mined. A dedicated development mining team continues
towards deployment during January to continue the acceleration of the
Ore extraction rates during December continued at an improved level.
Total rock mined during December averaged 612 tons per day. Ore mined
during December averaged 310 tons per day (a 29 day month due to
holidays), with development mining averaging 302 tons per day.
Overall, these mining rates represent an improvement over November.
The average daily ore mined represents about 68% of the targeted
design rate of 450 tons of ore per day, slightly better than
November, and roughly double the ore mining rate in October.
During December, the mine performance continued at an average of
nearly 5 rounds of mining progress per day, similar to performance
during November. (A round at Copperstone is eight feet of mining
advance resulting from one phase of drilling, blasting and mucking.
Although this varies according to rock type, one round at Copperstone
generally contains roughly 100 tons of rock).
Ore tonnage processed through the gold plant during December was
steady relative to performance in November. Ore processed during
December averaged 334 tons per day (28 operating days due to the
holidays), which is 74% of the designed rate of 450 tons per day. The
processing throughput is currently limited by tailings handling. This
limitation is currently being investigated with a view toward raising
the tonnage that can be pumped to the tailings impoundment. The
milling facility as designed is capable of processing higher tonnage,
and will do so in the future as the few remaining issues are
Mill recovery during December averaged 68%, reflecting the effects of
colder temperatures negatively impacting performance of the flotation
chemicals and availability of the normal chemicals requiring the use
of alternatives. These limitations have been addressed by heating
these reagents and finding alternate sources of chemicals. Initial
indications from the first ten days of January are encouraging, with
the recovery rate increasing to 81% for that period.
Ore processing rates are expected to improve when the tailings
management system issues are resolved, and early indications are that
the recovery rates are already improving. These two areas have the
potential to significantly improve the number of ounces of gold
recovered into concentrates.
Concentrate grades for the gravity circuit averaged 48 ounces of gold
per ton (November: 25 ounces of gold per ton), and the flotation
concentrate grades averaged 69 ounces of gold per ton (November: 13
ounces per ton). These concentrate grades are substantial
improvements over the November performance. A total of 1,118 ounces
of gold were recovered in concentrate during December, which is a
substantial improvement over the 650 ounces of gold that were
recovered in concentrate during November. The ounces of gold
recovered during December were primarily adversely impacted by gold
recovery rates in the mill, limitations on mill throughput, and
limitations resulting from mine tonnage output. Early indications are
that the shortcomings in the ore transport and handling systems
experienced in November have largely been resolved during December.
Mine and mill performance for the full month of January will be
announced during mid-February.
Mr. Brian Kirwin, President & CEO, commented: "We are encouraged by
recent progress from the underground mine, and the focus at
Copperstone is now to resolve the tonnage limitations in the mill and
continue improving the gold recovery rates. December's performance
shows a steady improvement as we work through the remaining
limitations, and we look forward to bringing the Copperstone gold
mine up to design throughput in the near future."
This release was reviewed by Douglas Wood, P.G., Vice President,
Exploration of Bonanza, a non-independent Qualified Person within the
meaning of NI 43-101.
Bonanza is operating the newly constructed Copperstone gold mine in
Arizona. For more information please visit Bonanza's website at
AMERICAN BONANZA GOLD CORP.
Brian Kirwin, President & Chief Executive Officer
We seek safe harbour.
American Bonanza Gold Corp.
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