Diseño De Circuito Optimo De Cobre

HOME
Designing the Optimal Flotation Circuit – The Prominent Hill Case
K E Barns1, P J Colbert2 and P D Munro3
ABSTRACT
OZ Minerals’ Prominent Hill copper-gold concentrator in South Australia was built in 2008 with commercial production commencing in early 2009. In addition to recovery of valuable minerals, the flow sheet for this iron oxide-hosted copper-gold deposit has to address the issueof producing a good quality saleable copper concentrate by high selectivity against non-sulfide gangue. Detailed mineralogical studies integrated with the metallurgical test work highlighted that liberation of fluorine-bearing minerals and subsequent very efficient rejection in cleaner flotation was necessary to produce a commercial quality copper-gold concentrate. Bench scale laboratorymetallurgical tests and mineralogical studies identified the need to regrind rougher concentrate to a P80 of 20 25 microns or finer for adequate liberation of the fluorine-bearing minerals. Satisfactory separation of the fluorine-rich gangue material from the valuable copper sulfides requires highly efficient cleaner flot- ation. This is done by a combination of washed froth cleaning and conventionaldilution cleaning. Proven equipment developed to meet similar taxing liberation and separation duties for the treatment of the refractory zinc-lead-silver ores of the Carpentaria-Mount Isa Mineral Province have been selected. The combination of Xstrata Technology’s IsaMill™ and Jameson Cell technologies addressed both the liberation and separation issues in the Prominent Hill concentrator. The energyefficient IsaMill™ technology both regrinds the rougher concentrate while its inert grinding environment prevents contamination of mineral surfaces with “debris’ ensuring subsequent optimum flotation performance. Heading up the cleaner circuit with a ‘scalping’ Jameson Cell followed by conventional flotation equipment allows this section to take advantage of the Jameson Cell’s high intensityflotation environment and froth washing capability to achieve maximum concentrate grade (at minimum fluorine levels) while maximising recovery through the use of conventional flotation machines. This paper looks at the development of the Prominent Hill flow sheet from the initial mineralogical and laboratory test work to the design, scale-up and early operation of the Prominent Hill regrind and cleanerflotation circuits. The mineralogically-based approach of domaining metallurgical ore types combined with the axiom of size-by-size mineral particle behaviour by liberation class gave a clear understanding of the liberation and separation issues involved in the processing of Prominent Hill ore. Technologies developed to meet much more onerous liberation and separation duties for the treatment ofthe refractory zinc-lead-silver ores of the Carpentaria-Mount Isa Mineral Province were successfully used to improve concentrate quality by rejecting non-sulfide gangue containing impurities. An IsaMill™ and a Jameson Cell are included in the circuit for fine grinding and for additional concentrate cleaning. Plant performance since commissioning has justified the approach for metallurgical testwork and equipment choices for the flotation circuit.

Project milestones are as follows:

• 2005: • prefeasibility study, • conceptual development plan, and • agreement on approval process with Primary Industries
and Resources South Australia;

• 2006: • bankable feasibility study, • issue of mining lease, • board approval for development, and • commencement of mining; • 2007: • projectdevelopment and construction, and • first ore reached October 2007; • 2008: • Oxiana Limited merges with Zinifex to form OZ Minerals
Limited, and

• operations team build-up; • 2009: • first production and sales February 2009, and • first concentrate exports from Port of Darwin in April
2009.

SCHEME OF METALLURGICAL TEST WORK
Given the nature of the Prominent Hill deposit, conventional...