Metalline has contracted Green Team International (GTI) to
complete a Bankable Feasibility Study on its Sierra Mojada
Project. The standards of a Bankable Feasibility Study are
of such quality that banks and international lending institutions
will lend project capital debt financing. The study will determine
the costs to mine and extract the zinc and any by-product
metals and apply economic analyses to determine the profitability
of
the project.
Metalline’s selection of GTI was partially due to
GTI’s experience conducting the feasibility study
for the Skorpion mine and their involvement in the project
execution up to hot commissioning. Norman Green, managing
member of GTI, was the Anglo Base Metals Project Manager
for the Skorpion Zinc Project, while other members of GTI
were deployed in area manager and various technical roles
in the integrated Anglo Base Metals Team. The Anglo Base
Metals Project Team was responsible for the overall management
of the EPCM contractor during project execution and commissioning.
After commissioning, various members of GTI remained involved
during the ramp-up phase to assist with operator training,
plant optimization and remedial work. The Skorpion mine
is the first, and to date the only, mine in the world using
the solvent extraction electrowinning process for extracting
Special High Grade zinc (SHG 99.995%) from oxide zinc ore.
The study metallurgical work has developed a flow sheet,
process, which concentrates the oxide zinc mineralization.
The host rocks containing the zinc mineralization consist
of iron oxide, limestone and dolomite. Limestone and dolomite
are carbonate rocks, which are acid consuming rocks that
adversely affect the acid leach economics. The
metallurgical work has successfully developed a process
using Dense Media Separation (DMS) and floatation, two standard
metallurgical technologies, to remove and reject the carbonate
minerals and concentrate the zinc minerals producing an
oxide zinc concentrate with low carbonate content and higher
zinc grade. Carbonate is about 65% of the
mineralized rock. Removing the carbonate improves the grade
from about 9%, to about 30% in the concentrate. Carbonate
removal reduces, by about 65%, the amount of material to
be leached; only the zinc minerals, about 35%, are leached.
Reducing acid consumption and the size of the leach circuit,
reduces the cost of leaching and the capital cost of the
leach circuit. The metallurgical results were announced
as a news release and a Form 8K on July 12, 2005.
Producing a high-grade concentrate improves economics over
direct leaching of the as mined mineralized material by
reducing acid consumption and capital costs. An important
additional advantage is that it allows the option of locating
the refinery site in the country that provides the best
economics relative to taxation, electricity cost, water,
equipment and transportation costs and other factors related
to the refinery, the extraction and reduction processes..
The mine and concentrator would be in Mexico, the refinery
could be in Mexico or another country offering better economics.
Refinery site location is being investigated as part of
the Feasibility Study.
The Mine Plan portion of the Feasibility Study has been
awarded to Pincock Allen & Holt, international mining
and financial consultants, as announced in a news release
dated April 10, 2006. The scope of work includes:
Geologic Review
Review of Resource Estimate and Methodology
Detailed mine plan Development
Mine Equipment Selection
Mine Capital Estimate
Mine Operating Cost Estimate
Development of an Ore Reserve Estimate
The Mine Plan will determine the mining method, production
rate and associated costs.
The metallurgy and mining data will be the basis for the
design of the refinery.