Update on Bisha Copper
Commissioning<
http://www.tesfanews.net/update-on-bisha-copper-commissioning/>
Posted on 30 October 2013. Tags: bisha <
http://www.tesfanews.net/tag/bisha/>
*Nevsun is operator of the Bisha Mine, one of the highest grade open pit copper
mines in the world. With a strong balance sheet and future cash flow,
Nevsun is positioned for growth while maintaining a strong dividend.*
Nevsun and Bisha. Copper Production, Disciplined Growth.
By* Nevsun* <
http://www.nevsun.com/news/2013/october30/>,
*Nevsun Resources Ltd. <
http://www.nevsun.com/> (TSX:NSU / NYSE MKT:NSU) *is
pleased to announce commissioning of the new copper flotation plant is
progressing well with continued production of saleable copper concentrate
and commercial production expected before the end of year.
*HIGHLIGHTS*
- Commercial production now expected before the end of this year
- Commissioned rougher flotation and filter press circuits using pyrite
sand ore in June
- Commissioned cleaner and regrind circuits using low grade supergene
ore in August
- Outstanding punch list items and minor commissioning modifications
well progressed
- Flotation plant throughput now approaching 70 percent of 2014 plan
- Copper recoveries now approaching 80 percent of 2014 plan
The initial plant commissioning commenced in June 2013 and first
produced a precious
metalsconcentrate from pyrite sands ore, which was followed by the
production of lower grade copper-gold-silver concentrate in August 2013.
Since mid-August 2013 there has been a steady improvement in plant
stability. The plant has been operated at lower than design throughputs
during this commissioning phase as the Company cautiously advances the
project. The commissioning with pyrite sands caused some premature wear to
part of the plant including cyclone feed pump internals, piping and valves,
particularly in the flotation circuit, however once the feed transitioned
to planned supergene ore, both corrosion and abrasion effects significantly
declined. Minor plant design modifications and rectification of these worn
components has been systematic in approach and thus far successful. Steel
piping in certain sections evidencing high wear is being replaced with high
density polyethylene piping, various critical steel
pumps<
http://www.tesfanews.net/update-on-bisha-copper-commissioning/#>
with stainless steel equivalents, and high wear sections to be reinforced
with ceramics and chrome, rubber linings or epoxy.[image: Nevsun and Bisha.
Copper Production, Disciplined
Growth.]<
http://www.tesfanews.net/update-on-bisha-copper-commissioning/copper_mining_bisha/>
Two notable issues requiring extra attention involved the flotation
conditioning tank<
http://www.tesfanews.net/update-on-bisha-copper-commissioning/#>and
the rougher flotation dart valves. For the conditioning tank, whose main
function is to alleviate surge to the rougher flotation cells while
properly conditioning the ore slurry with reagents, the
tank<
http://www.tesfanews.net/update-on-bisha-copper-commissioning/#>
bottom
suffered significant corrosion from the abrasive pyrite sands. Temporary
tank <
http://www.tesfanews.net/update-on-bisha-copper-commissioning/#>repairs
will be complete by early November 2013.
In 2014 a new section of the
tank<
http://www.tesfanews.net/update-on-bisha-copper-commissioning/#>
will
be installed and the tank will be lined with epoxy. The plant is able to
continue operating with a conditioning tank by-pass but throughput is a
somewhat reduced. The second issue involved damage to the rougher flotation
dart valve shafts due to*siltation* in the tanks from the high density
pyrite sands. Most of these bent shafts have been straightened, with the
option to replace some in the future with more robust shafts. All
conditions noted above will be monitored. The cost of these fixes has not
been significant in relation to
theinvestment<
http://www.tesfanews.net/update-on-bisha-copper-commissioning/#>
with
capital for copper flotation plant completion still well below budget.
Copper concentrate continues to be produced in sufficient quantities with
two additional shipments planned for November 2013 following the two
shipments already completed in October 2013.
Copper recovery improvements are expected to grow to over 80% and these
levels are anticipated once the design target grind size of the ore is
achieved, expected after the conditioning
tank<
http://www.tesfanews.net/update-on-bisha-copper-commissioning/#>
and
dart valves are fully operational thus allowing the regrind mills to
function at full capacity. Likewise, the introduction of non-acidic process
water for flushing, spray water and hosing purposes as well as chromium
coated grinding media to reduce grinding media consumption are assisting in
further achieving this goal.
Two of the regrind mills are currently operating while the remaining two
will be commissioned when throughput increases.
The entire front end of the plant, consisting of crushing and grinding
circuit, as well as the back end of the plant, which includes tailings
thickening and discharge, is the same as used during the gold phase and
accordingly no commissioning was required.
Commissioning of the project will continue through the upcoming months as
these final repairsare completed and the plant monitored. The remainder of
commissioning activities this year will focus on increasing throughput and
improving recoveries and concentrate grades.
The Company expects to achieve commercial production before the end of 2013.
Received on Thu Oct 31 2013 - 14:40:29 EDT