One thing that is certain about the Ulan mine in the New South Wales Western Coalfield is that production rates are going to go up. Currently, the mine is undergoing a major face-lift under the direction of new owner Enex Resources (previously Glencore) which bought Ulan from oil major Exxon earlier this year.
The immediate aims of a new management structure and reorganised workforce have been achieved and have delivered early results: worker morale has improved significantly, and the mine generated record output of 507,000 tonnes in May.
Since April, when Enex took control of the site, a number of changes had been implemented, said operations manager Nev McAlary. A more traditional management structure, with direct responsibility and accountability accepted by individual managers, had been put in place, total workforce numbers had been reduced (primarily management/staff numbers) and a long due overhaul of the conveyor system was carried out.
McAlary said the mine was working to “higher operating standards”. The opencut mine and washplant workforce was cut by more than 25%, while underground operations management, including frontline supervisors, was almost halved (by 53) to 63 people. Cost savings in wages alone are forecast at more than $5 million a year.
With a modest projected mine life remaining in the opencut operation, Enex elected in April to contract the operation of this part of the mine to Roche Mining.
“With the opencut operations having approximately seven years life Enex decided to focus its efforts on the long-term success of the underground operations,” McAlary said.
Enex has retained operational management of the underground operations and early changes have included the introduction of cost control, performance monitoring and practical safety measures.
“I believe there are a lot of benefits to be gained at Ulan right now through the operation being run by a coal mining company, through the application of sound mining practices, and through understanding the potential of the entire 10m Ulan seam,” McAlary said.
Results suggest Enex is on the right track. The record May production total helped lift Ulan’s average monthly production for the June 2001 quarter to 430,000t, compared with the average in the corresponding quarter last year of 230,000t, while free-on-board (FOB) cash costs were lower. Key objectives for 2002 will be further reducing FOB cash costs as well as maintaining longwall continuity around igneous geological features, which means three longwall changeouts could be needed in 2003.
Improved longwall equipment utilisation is also high on the agenda with a target of 90 cutting hours per week. And higher cutting rates of around 1400t per cutting hour off the longwall are being investigated. Other aims included reducing the longwall changeout schedule; increasing the time between equipment overhaul to between 4-6 million tonnes; and enhancing maintenance management through an integrated condition monitoring program. McAlary said the mine had also set new safety goals.
“Ulan has excellent but extensive safety systems and features,” he said. “These require consolidation and rationalisation. Our target is to remain in the lowest quartile of industry performance regarding our safety statistics.”
With much of the initial restructuring completed, mine management is now turning its sights to the longer-term future of the vast deposit, which hosts estimated underground resources (measured and indicated) of 287.9Mt and marketable reserves totalling about 179.2Mt. Under the existing mine plan, Ulan has a 40-year mine life at a production rate of 4Mt per annum. Currently being evaluated are various long-term strategic options, including increasing longwall panel width to 400m, adopting the longwall top coal caving method, adding a second longwall, and using a tunnel boring machine for driving mains development.
The 10m-thick Ulan seam is exploited via both opencut and underground methods. In the opencut operation, the top 7m (roughly 1Mtpa) goes to the nearby Eraring power station under contract, and the bottom 3m is exported. The longwall mines 2.9-3m, leaving around 7m of coal in the roof. Top coal caving, developed in China, is a high-capacity coal mining method that can extract full seams of up to 12m. The technology is being introduced into Australia in conjunction with Chinese coal producer Yankuang, the CSIRO and University of NSW.
In addition, Ulan is reviewing the development of an overland conveyor system to replace the current myriad of outbye conveyors, a move that will become imperative if Enex seeks to boost underground production capacity.
Current longwall roof supports — Joy/Dowty four-leg shields — reach the end of their lifecycle at the completion of longwall 22 (in 2004-05). New supports will probably be required, and will also permit a face extension to be undertaken from current widths of about 250m to 380m — the “fat face project” as it is known at the mine site. One option is to develop a second longwall with the current (refurbished) supports in the western part of the lease.
Whatever the outcome, Enex has big plans for Ulan.
