Environment Case Studies
Environment – Stewardship
- Case Study Contributor:
- BHP Billiton Mitsubishi Alliance (BMA) (Peak Downs Mine)
- BHP Billiton Interest:
- 50%
- Location:
- Central Queensland, Australia
- Customer Sector Group:
- Carbon Steel Materials
- Commodity:
- Metallurgical and Thermal Coal
- Case Study Status:
- New for 2006
Peak Downs Mine Initiates the Last Drop Project to Minimise Coal Loss During the Mining Process
- Every ‘last drop’ helps to meet the global demand for hard coking coal
Peak Downs is one of a number of mines operated by BMA in the Bowen Basin producing hard coking coal (HCC). There are limited HCC resources in the world, which puts Peak Downs in a privileged position with strong demand and good prices for its products.
An issue faced by BMA has been the amount of coal lost during the waste stripping and mining process. Studies had shown that the loss can be as high as 13 per cent. Initial work indicated that it is possible to reduce this loss by 5 to 8 per cent, but new work practices and significant process changes are required.
The BMA Business Improvement and Optimisation Group and Peak Downs management initiated a project to look at options and seek a solution. The result is a new process that has been shown to not only reduce coal loss by approximately 9 per cent but also deliver other benefits that can contribute significantly to BMA’s sustainability performance.
The challenge
A project team was formed comprising personnel from the Peak Downs mining and technical services departments, BMA Business Improvement staff and consultants from the strategic services firm Global Mining Corporation. The team set out to gain an understanding of the current level of coal loss suffered during waste stripping and mining at Peak Downs, identify the causes of this loss and develop a new core process for the mining operation. As the goal is to mine every 'last drop' of coal from the deposit, the initiative was named the Last Drop Project.
The process
Last Drop concept, pre-feasibility and field trials
The current level of coal loss in the mining processes was measured at 11.5 per cent. Causes of coal loss were found to include direct blast damage to the top of the coal seam, digging off the coal by large waste-stripping equipment such as draglines, blast shear to the front edge of the coal seam, and general damage from trucks and diggers running on coal.
A loss minimisation concept study delivered several options, one of which showed clear economic potential. A pre-feasibility study followed, with extensive participation by Peak Downs operations and technical personnel to test the practicality of the option and refine the solution. The result is an innovative concept based on leaving a 'hardcap' of waste (approximately 1.5 metres thick) on top of the coal, so that blasting does not 'damage' the coal and major equipment never touches it. Precision is the key:
- in drilling and blasting of the waste overlying the coal
- in the new mining process used to remove the hardcap without losing coal.
Approval was received to conduct a program of full-scale field trials to test this solution and determine the likely reduction in coal loss. Extensive field trials over 15 months showed that using the hardcap mining process can reduce coal loss to 3 per cent (i.e., a reduction of 8.5 per cent) without compromising safety or production.
Last Drop feasibility study
A feasibility study is being undertaken to define the resultant benefits of adopting this new process at Peak Downs. As part of this study, an implementation plan is being developed by the project team in consultation with site management. This plan covers the resources, new work process and organisational change required to realise the value that the Last Drop Project can deliver.
The changes necessary to make the Last Drop initiative work do not involve advanced technology nor is any major capital required. What is necessary is a much more disciplined approach to operations and different types of work from operations and technical staff. This includes providing high-quality, detailed information to engineers, efficient working relationships between different departments based on well-designed systems and processes, and a rigorous planning and reconciliation process. The aim is to produce a routine and predictable work flow.
The successful implementation of the Last Drop project is based on the involvement of key operational, technical and managerial personnel in the organisational design,; including the systems, processes, work design, culture and structure.
The outcomes
As well as reducing current coal loss by approximately 9 per cent and mine site cash costs by around 8 per cent, the Last Drop process delivers a number of other benefits that contribute significantly to BMA’s sustainability performance. These include (relative to the current plan for the same sales):
- conserving the coal resource by adding approximately three years to the current 30-year mine plan
- reducing the area disturbed by mining by 50 hectares per annum
- reducing truck or shovel stripping by approximately 13 million bank cubic metres annually, a 20 per cent reduction across the site (note: a bank cubic metre represents one cubic metre of material measured prior to disturbance)
- reducing explosives consumption by approximately 18 per cent, with consequent greenhouse gas benefits
- reducing annual diesel fuel consumption by 9 million litres and the usage of large earthmoving tyres by approximately 40 tyres each year, also with consequent greenhouse gas benefits
- reducing waste taken to the plant each year by 600,000 tonnes, with a corresponding reduction in plant rejects
- assisting to achieve the BHP Billiton Group target of a reduction in greenhouse gas emissions per unit of production of 5 per cent by 30 June 2007.
Overall, the benefits delivered by the Last Drop Project demonstrate that it is possible to enhance the sustainability of the business while also increasing economic value.
Coal loss after typical mining process measured 353 mm, July 2004
Coal loss after Last Drop process measured 82 mm, August 2005
