High efficiencies for Perilya Broken Hill from turnkey on-stream analysis system

Outokumpu Technology package to give major production benefits and cost efficiencies at historic orebody.

One of the world’s most advanced on-stream slurry analysers is to be installed by Outokumpu Technology at Perilya’s Broken Hill lead, zinc and silver mine in New South Wales, Australia. The Courier® 6 SL elemental analyser system is part of a turnkey package of analysis, automation and sampling technology designed to optimize recoveries and concentrate quality.  It will also save costs, time and valuable labour at the mine, which is one of the country’s largest lead, zinc and silver operations. Benefits will include improved process control and assay efficiency and also greater reliability compared with existing older systems, which require continual maintenance to ensure operability, explained Outokumpu Technology’s Service Centre Manager in Australia, Jason King.

Perilya currently produces about 2 Mt/y at the historic Broken Hill orebody, which was one of the foundations of the Australian Mining industry and which has produced more than 200 Mt of ore over the 121 years since mining commenced in 1885.  Since acquiring, Perilya has made significant improvements in the operations, including underground equipment replacement and optimization of its concentrator. 

The state-of-the-art Courier 6 SL system – which includes metallurgical and primary samplers, sample drying system, sample pumps, piping, platforms and electrical and mechanical installations – will replace the existing and increasingly ageing analyser system at Perilya.  The new system is designed to further extend the mine’s efficiency gains, while also being simpler and faster to operate, says King.

“This turnkey automation and analysis system is a great endorsement of our technology and people. The strength and scale of our solutions is reflected in the fact that we have already successfully provided Perilya with float technology in the past.  This latest turnkey package will deliver major production benefits and cost efficiencies,” he added. “While the project is still in its infancy, it is progressing smoothly because of the collaborative efforts of Perilya and Outokumpu Technology. This partnership approach will ensure that project challenges which arise will be met with enthusiasm and dedication.”

Outokumpu Technology’s Eric Hendrix, one of the managers on the Perilya project, explained that the turnkey system includes full design, removal of existing equipment, and installation of the Courier 6 SL and all peripheral works, such as piping, sample pumps and all associated structural and mechanical works.  Electrical installation also forms an important part of the project scope. 

A spokesperson from Perilya said that, safety, efficiency gains and simplicity were important considerations in the introduction of a new system, which could reduce the number of radiation sources on-site, thus minimising risk and reducing the regulatory burden. “Electronic X-ray production facilitates higher count rates than those possible with typical radioisotopes. This translates into improved instrument sensitivity. Also, no additional reagents are required (e.g. liquid nitrogen). This eliminates the introduction of a hazard on-site,” the spokesperson explained.

Outokumpu Technology says the Courier 6 SL analyser system is the highest performance model in a new generation of real time on-stream elemental slurry analysers. They enable quick and accurate analysis and maximize process efficiency. Based on the same high performance wavelength dispersive XRF technology as used in laboratories, the Courier 6 SL offers the best sensitivity and short cycle time for process management, monitoring and control.

Sampling, analysis and sample return are fully automatic, do not require operator attendance and are automatically done in the same consistent way around the clock. This creates savings in assaying costs and metallurgical sampling. Concentrate recoveries are also better, as process upsets are detected and solved rapidly. Plant operation is optimized with less circulating loads, resulting in higher throughput.

Installation of the turnkey system – to be completed by early 2007 – is being managed by Outokumpu Technology’s Service Centre in Australia.

Perilya’s Broken Hill Operation produces two products, a zinc concentrate and a lead concentrate. Being of low complexity and having a grade of about 50% Zn and 70% Pb, respectively, concentrates from Broken Hill are a premium coarse-grained product. Perilya aims to make its Broken Hill mine, one of the largest historic base metal mines in the world, a model of highly profitable and successful operation.

Perilya Broken Hill Ltd (Perilya) acquired the Broken Hill mine from Pasminco in May 2002, together with a number of exploration tenements in the surrounding area. Perilya now manages 1,024 km2 kilometres of prospective terrain which includes the mine leases, incorporating the Southern Operations, the North Mine, and the Potosi Trend, and the historic Little Broken Hill and Pinnacles areas.

Mining under Perilya’s management commenced in July 2002 and after three years stabilized at a mining and processing rate of about 2 Mt/y. In the year 2004/05, the Southern Operations produced 1.8 Mt of ore and the North Mine 100,000 t. At the same time the concentrator output was 261,000 t of zinc concentrate, containing 132,000 t of zinc, and 85,000 t of lead concentrate, containing 61,100 t of lead and 1.9 Moz of silver. Current projections are that mining will continue until at least 2011, before the known ore reserves are exhausted, but Perilya is confident it will be able to extend the mine life by defining additional ore reserves and mineral resources.

The Southern Operations underground workings are accessed by three shafts and a decline. The shafts include the Main Haulage shaft, the Main Service Shaft and the Southern Cross Shaft. At its current deepest point, the mine reaches about 1,200 m below surface and there are more than 90 km of accessible drives. Ore haulage is via the Main Shaft, although there is some haulage capacity in the Southern Cross Shaft. The drive-down decline is a 5.5 m x 5.0 m ramp from the surface, which connects into the existing underground ramp system and facilitates the delivery of materials and heavy equipment to all parts of the mine.

Mining is principally conducted using a longhole open stope method with variations developed for extraction of the secondary resource located in the previously worked pillars area. Longhole stoping currently accounts for 85% of underground production, with pillar extraction and development ore contributing 5% and 10% respectively of the total. The ventilation system comprises ten ventilation shafts with three surface exhaust fans and one surface intake fan.

Both concentrates are railed to Port Pirie, South Australia. Approximately 50% of the zinc concentrate is currently sold to Korea Zinc Co with the remainder sold to Zinifex for treatment at its Risdon zinc smelter. The lead concentrate is currently sold to Zinifex for treatment at its Port Pirie lead smelter.

At the North Mine, where production is being sourced from the upper levels, a pre-feasibility study into the viability of mining the lower levels has commenced.