Post by AJrWennerGren on Jun 24, 2004 21:16:44 GMT -5
Caledonia Mining Corp.'s - Barbrook Gold Mines Ltd
The 100% owned Barbrook Mines Limited
("Barbrook")
is located near the town of Barberton in
the Mpumalanga province of the Republic of
South Africa.
Pretoria and Johannesburg are approximately 375 km
to the west.
Barberton is the natural and historic center of
the Barberton goldfield in the Mpumalanga province.
The town has a history of mining dating back more
than 100 years.
Barbrook's mining licence covers an area of
approximately 43 square kilometres (10,625 acres),
extends for a distance of about 28 km along strike,
and is the consolidated mining area of
about 20 old Gold Mines, of which some
produced Gold in more than 50 years.
Barbrook Gold Mines Ltd.
RE: Plant Testing and Modifications;
Testing:
A number of alternative metallurgical circuits to improve
the gold recovery have been tested and circuit improvements
have been identified.
In late 2003 and early 2004 Caledonia introduced new
flotation equipment and concentrate oxidation technology
at Barbrook to improve the gold recovery and
production economics.
In early 2004, Barbrook commenced the evaluation of
"ultra-fine milling" and "whole-plant Biox®" processes
to determine whether further gold recovery improvements
and improved economics can be attained.
As further test work is completed on these process
alternatives, and following on the feasibility study,
more revisions to the metallurgical plant are expected.
Modifications:
Between late February and early May 2004
the operations at the plant were temporarily
suspended to carry out modifications which
would improve metallurgical Gold
recovery and increase
throughput from...
6,000 tonnes per day (tpd)
to 8,000 tonnes per day (tpd).
The plant modifications included:
Installation of a "fines washing and screening" section
in the crusher circuit to improve the existing crushing
and screening efficiency and to allow for a finer
screening size of the crusher product.
As tests at Barbrook and SGS Lakefield laboratories
in Johannesburg had shown that satisfactory flotation
gold recovery could be achieved at coarser feed ore
sizings, the Barbrook mill (that previously milled to
a product size of about 85% minus 75 microns) was
reconfigured to produce a coarser grind to about
65 to 75% minus 75 microns.
This should increase the mill throughput to
about 8000 tonnes per month or higher.
An "organic carbon pre-float" circuit was added to
the front of the flotation circuit to remove much
of this 'preg-robbing' material from the circuit.
This should reduce the amount of blinding agent added
in the leach circuit and consequently reduce the
foaming problem in RIL.
A second G-cell has been installed in flotation for
re-cleaning of the cleaner flotation concentrate.
This is expected to increase the gold grade in the
final concentrate product whilst maintaining gold
recovery and make operation of the flotation
section less complex.
Changes have been made in the regrind/thickener
section to achieve finer regrind sizes and more
consistent concentrate feed densities to leaching.
The PreOx and intensive agitation sections have
been replaced by 2 Aachen oxygen dispersion units.
Pilot plant tests at Barbrook have shown these units
provide excellent oxygenation of the fine reground
flotation concentrate and lead to more consistent
leach gold recoveries.
The primary Aachen unit performs most of the oxygen
demand requirements and the secondary unit is used
to promote rapid cyanidation and maintain oxygen
levels into the RIL section.
Automatic cyanide measurement and addition has been
installed in the RIL section to optimize gold recovery
and reduce cyanide consumption.
The size of the elution facility for loaded resin has
been increased.
This will allow for improved gold security and greater
flexibility of RIL operation.
It is expected that the above plant changes should
enable the mine attain a sustainable economic operation
on Taylors ore until the Biox® or the
"ultra-fine milling" processes have been fully
tested and evaluated.
Mine Development and Planning:
In 2004 it has been decided to develop mining
operations at Taylors on the Barbrook line
below the 10 level, at the upper levels of Taylors
and easterly along strike towards the Crescent area
and on the Zwartkoppies line in order to provide
additional ore to the metallurgical plant when
the new metallurgical processes are
proven successful.
The old mining areas above 7 level in the "French Bob"
structure have been re-evaluated and the Mine is
currently re-opening these for production.
GOT CAL GOLD MINES SHARES ?
www.ivarkreuger.com/mining.htm
Imo. pass it along>>>>>>>>>>>
The 100% owned Barbrook Mines Limited
("Barbrook")
is located near the town of Barberton in
the Mpumalanga province of the Republic of
South Africa.
Pretoria and Johannesburg are approximately 375 km
to the west.
Barberton is the natural and historic center of
the Barberton goldfield in the Mpumalanga province.
The town has a history of mining dating back more
than 100 years.
Barbrook's mining licence covers an area of
approximately 43 square kilometres (10,625 acres),
extends for a distance of about 28 km along strike,
and is the consolidated mining area of
about 20 old Gold Mines, of which some
produced Gold in more than 50 years.
Barbrook Gold Mines Ltd.
RE: Plant Testing and Modifications;
Testing:
A number of alternative metallurgical circuits to improve
the gold recovery have been tested and circuit improvements
have been identified.
In late 2003 and early 2004 Caledonia introduced new
flotation equipment and concentrate oxidation technology
at Barbrook to improve the gold recovery and
production economics.
In early 2004, Barbrook commenced the evaluation of
"ultra-fine milling" and "whole-plant Biox®" processes
to determine whether further gold recovery improvements
and improved economics can be attained.
As further test work is completed on these process
alternatives, and following on the feasibility study,
more revisions to the metallurgical plant are expected.
Modifications:
Between late February and early May 2004
the operations at the plant were temporarily
suspended to carry out modifications which
would improve metallurgical Gold
recovery and increase
throughput from...
6,000 tonnes per day (tpd)
to 8,000 tonnes per day (tpd).
The plant modifications included:
Installation of a "fines washing and screening" section
in the crusher circuit to improve the existing crushing
and screening efficiency and to allow for a finer
screening size of the crusher product.
As tests at Barbrook and SGS Lakefield laboratories
in Johannesburg had shown that satisfactory flotation
gold recovery could be achieved at coarser feed ore
sizings, the Barbrook mill (that previously milled to
a product size of about 85% minus 75 microns) was
reconfigured to produce a coarser grind to about
65 to 75% minus 75 microns.
This should increase the mill throughput to
about 8000 tonnes per month or higher.
An "organic carbon pre-float" circuit was added to
the front of the flotation circuit to remove much
of this 'preg-robbing' material from the circuit.
This should reduce the amount of blinding agent added
in the leach circuit and consequently reduce the
foaming problem in RIL.
A second G-cell has been installed in flotation for
re-cleaning of the cleaner flotation concentrate.
This is expected to increase the gold grade in the
final concentrate product whilst maintaining gold
recovery and make operation of the flotation
section less complex.
Changes have been made in the regrind/thickener
section to achieve finer regrind sizes and more
consistent concentrate feed densities to leaching.
The PreOx and intensive agitation sections have
been replaced by 2 Aachen oxygen dispersion units.
Pilot plant tests at Barbrook have shown these units
provide excellent oxygenation of the fine reground
flotation concentrate and lead to more consistent
leach gold recoveries.
The primary Aachen unit performs most of the oxygen
demand requirements and the secondary unit is used
to promote rapid cyanidation and maintain oxygen
levels into the RIL section.
Automatic cyanide measurement and addition has been
installed in the RIL section to optimize gold recovery
and reduce cyanide consumption.
The size of the elution facility for loaded resin has
been increased.
This will allow for improved gold security and greater
flexibility of RIL operation.
It is expected that the above plant changes should
enable the mine attain a sustainable economic operation
on Taylors ore until the Biox® or the
"ultra-fine milling" processes have been fully
tested and evaluated.
Mine Development and Planning:
In 2004 it has been decided to develop mining
operations at Taylors on the Barbrook line
below the 10 level, at the upper levels of Taylors
and easterly along strike towards the Crescent area
and on the Zwartkoppies line in order to provide
additional ore to the metallurgical plant when
the new metallurgical processes are
proven successful.
The old mining areas above 7 level in the "French Bob"
structure have been re-evaluated and the Mine is
currently re-opening these for production.
GOT CAL GOLD MINES SHARES ?
www.ivarkreuger.com/mining.htm
Imo. pass it along>>>>>>>>>>>
