MINE EXCURSION
the town of Prieska, located on the banks of the fertile
Orange River. The mine will send on average between 20
to 24 truckloads of concentrate a day to a rail siding 50km
away, where it will be put on the Transnet line to Coega in
Port Elizabeth, 800km to the southeast.
Orion has entered into a Memorandum of Understanding
with Australian Byrnecut Offshore. Byrnecut will be doing
the mine development while, similarly, Minopex have
been co-opted to look at operating the ore processing
plant. juwi Renewable Energies, the Cape Town based
subsidiary of international project developer juwi AG,
and Repli Trading No 27, a subsidiary of Orion Minerals,
recently entered into a collaboration agreement to
investigate generating renewable energy at the Prieska
mine, and juwi will generate and supply 35MW of
electricity from a hybrid power system using integrated
wind and solar technologies. The renewable energy
generation site will fall within 20km of the project
site, making the establishment of a dedicated feed via
overhead power transmission line possible.
The infrastructural advantages will make mining easier at
Prieska. Moreover, the copper zinc project could be the
start of a whole new mining complex in the Northern Cape.
These deposits usually occur in clusters and Orion holds
several licenses on land where there is a lot of potential for
further discoveries. Moreover, the company is undertaking a
number of additional exploration projects at sites with good
prospects for nickel and cobalt, minerals that will be in high
demand in the future.
Orion’s Prieska project is one of the few new mining
developments in South Africa, and certainly a trailblazer in the
Northern Cape. It is certainly a project to keep an eye on this
year.
Following the successful conclusion of value engineering
studies on the ore processing plant design and layouts Orion
recently placed orders and secured specific mills required to
realise the identified improvements.
According to Smart, the company can now begin to lock
in the anticipated project optimisations with associated
positive capex and opex savings. “The plant optimisation
studies progressed alongside studies on improved
water treatment and optimisation of our mine-to-
market schedule, all of which are nearing completion.
The successful metallurgical optimisation of the process
flowsheet has culminated in the opportunistic purchase
of two unused, pre-owned mills which are available at a
significant discount to mills which would otherwise have
to be placed on order as a long-lead item,” says Smart.
Walter Shamu, chief operating officer at Orion Minerals.
The two 3600kW mills consist of a 16.5-foot diameter x
27-foot long ball mill and a 22-foot diameter x 26-foot
semi-autogenous grinding (SAG) mill, complete with
all motors, gearboxes, ancillary fittings with associated
commissioning spares.
Securing these pre-owned but unused mills facilitates
the incorporation of SAG milling into the ore processing
flowsheet, in place of the ball milling arrangement selected
in the Prieska Project Bankable Feasibility Study (BFS).
The revised ball and SAG mill configuration will allow
significant operational flexibility and facilitate processing of
Prieska ore at a rate of up to 20% above design throughput,
allowing capacity for future expansion.
Contract workers sending cables down the shaft.
The use of SAG milling simplifies plant layout and operation,
with significantly reduced upfront capital expenditure and
a reduction in estimated operating cost, removing the
requirement for multi-stage crushing and screening of rock
ahead of milling.
Overall capital expenditure for the processing plant has
been reduced by about AUD15-million from the total
plant capital, originally estimated at AUD109-million
and the plant unit operating costs reduced by 5% from
a base estimate of AUD16.10 per tonne. This represents
a significant improvement to be incorporated into the
optimised and updated BFS report, due for completion in
the second quarter of 2020.
www. africanmining.co.za
African Mining Publication
Errol Smart, president and CEO of Orion Minerals.
African Mining
African Mining April 2020
15