New life for Awaba

AWABA Colliery wins the Australian Mine of the Year Award sponsored by MMD Australia. Daniel Hall writes

While productivity has become increasingly important for mine operators since the beginning of the resources boom, productivity alone is no longer the sole target for the mining industry.

Mine operators must juggle safety, recruitment, labour retention, technology, and environmental standards to attain a model of best practice.

The 2007 Prospect Awards celebrates a mine that is not the biggest, but has proved to be the best.

As tonnes are pushed through the supply chain, little thought is given to mines that are reaching the end of their life, let alone the workforce that has to re-consider their future employment prospects.

One coal mine has proved that even small mines can make a valuable contribution.

Awaba Colliery has engaged the mine’s workers and developed an innovative whole-of-mine approach to a challenging situation.

The colliery was to complete primary development work and undertake a minimal amount of pillar splitting as production slowed at the mine.

As a result of a change to colliery management, the life of the operation was re-assessed and extended by more than two years.

A successful extension to the mining operation was calculated to add two million tonnes of saleable product.

At projected operating costs, and if current market prices were maintained, this would generate an additional $25 million of revenue for Centennial Coal.

A significant area of old pillar panels existed at the colliery, which had the ability to be mined by secondary extraction methods.

There were also a number of small, previously discounted blocks of coal, which had the potential to be accessed and mined by conventional pillaring.

Following careful consideration and mine planning, mine management decided to undertake partial secondary extraction using mobile roof supports.

Pillars within panels less than 100 m wide were stripped by a maximum of 15 m, leaving small ‘stooks’ to manage wind-blast hazard. This left a row of standing pillars, which had the ability to carry the Teralba Conglomerate roof. This layout ensures that floor failure will not result in rapid and uncontrolled collapse of the strata above the extraction panels.

Where very low strength material is present, the hazard is managed by testing the floor prior to extraction, and any unsafe areas are excluded from the extraction plan.

The preparation of a Section 138 application and a Subsidence Management Plan (SMP) had to be completed to receive permission for secondary extraction.

The existing 138 approval, granted to the colliery in 1982, could no longer be used, as the date for renewal had expired in March 2005.

A new application was lodged, and work was undertaken to meet Subsidence Management Plan requirements.

Agreement also had to be reached with other key stakeholders, principally RailCorp, who owned infrastructure in the area.

A conservative plan was adopted, with more barriers installed between the workings and the Main Northern Railway Line than the prescribed guidelines recommended. This was an attempt to reduce the length of time the Interagency Committee needed to consider the Subsidence Management Plan.

Awaba Colliery could not afford protracted mining consultations and intensive post mining management of the railway line.

The existing infrastructure of 1050 mm conveyors and the coal screening plant were refurbished to support the proposed extension to the mine.

Likewise, power reticulation and a complex system of dewatering pumps were overhauled to meet the requirements of the operation.

Financial Analysis

A project financial analysis was undertaken based on key assumptions of ash content, tonnage, market, operational cost, capital, and overhead costs.

The three-year production schedule was proposed, with the colliery exporting a 14% ash steaming coal.

First-year production levels were held in line with the previous year’s budget.

Sensitivity analysis was conducted on the business plan, with sales price, exchange rate fluctuations, and yield being examined. It was confirmed that the Run of Mine coal yield would have a significant effect on the viability of the operation. It was important that yields were maintained at the budgeted level, otherwise profit margins would be eroded.

Awaba management found that each 1% variation to yield would cause a variation of $320,000 per annum to revenue.

A 1% variation in selling price resulting from a change in exchange rates would have a similar impact upon revenue.

Labour

Optimising the small Awaba workforce was very important for a successful mine extension.

A tailored approach to workforce consultation has been adopted by mine manager Keith Falconer, and the strategy has proved successful for mine management.

“Not all mine’s can position themselves as an employer of choice by putting dollars in front of people, we simply do not have the funds available to do that,” Falconer told Australian Mining.

“Mine’s looking to position themselves as an employer of choice must work towards a good working relationship with their employees,” he said.

A forum for regular communication kept workers informed in the planning process, and in ongoing work at the mine.

Mine management saw communication as an important part of the extension, as increased preparation work would result in fewer resources allocated to general production.

Open communication maintained the enthusiasm of the stretched workforce, and retained the company’s highly skilled personnel as the operation drew to a close.

“What we have been able to achieve with this project is proof that our strategy to engage workers in the goals and targets of the operation was a success,” Falconer said.

Upon receiving the Australian Mine of the Year trophy, Falconer paid tribute to workers at the Awaba colliery, past and present.

The colliery is celebrating its 60th anniversary, with production at Awaba commencing in 1947.

“The power station which the colliery was built to supply has closed, as has the railway that was built to supply the mine,” Falconer said.

“The colliery is still going strong as a result of the hard work that workers are prepared to put in.”

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