Coal Compaction (10kJ Landpac Impact Compactor)	CIR Plot

In order to eliminate the risk of spontaneous combustion of coal discard dumps, it is necessary to compact the coal discard as it is placed in layers to allow for the reduction in air voids that contain the oxygen that could fuel the combustion process.

Landpac ground improvement technologies are capable of achieving thick-lift compaction of coal discard, in layers of around 500mm. These capabilities allow for vastly increased productivity rates and complete “in process” quality control monitoring that result in greatly improved utilisation of the placement equipment and reduced compaction testing costs, whilst ensuring a far greater level of quality assurance than can be achieved using conventional compaction equipment.

Productivity Advantages of Thick-lift Layer works

The ability of Landpac ground improvement technologies to compact in thick lift layers has a number of productivity advantages.
The most obvious advantage is that a far greater volume of coal discard can be compacted to specification in any time period using Landpac ground improvement equipment than could be compacted using conventional equipment.

Another advantage of using thick-lift layer works is that the cost of placement of any given volume of material is reduced because of a lesser requirement for levelling works. Typically, one thick-lift layer that can be compacted using Landpac ground improvement equipment would equate to 2 to 3 thin-lift layers that would be required for compaction using conventional compaction equipment. This obviously reduces the amount of time and equipment (e.g. Bulldozers, graders etc) that would need to be utilised for layer levelling by a factor of between 2 to 3 times for any given volume of coal discard.

Quality Assurance Advantages

The Landpac CIR and CIS technologies allow for constant “in process” monitoring of the thick-lift layer works compaction. This allows for the following advantages:
- Monitoring of 100% of the coal discard being compacted.
- Recording of the relative compaction and strength of the entire area of each layer being compacted.
- Identification of focussed areas for conventional testing. By utilising the CIR maps to extrapolate the conventional test results over the entire compaction area it is possible to reduce the number of conventional tests required. In this manner, the certainty of the entire volume of coal discard being compacted with specification can be greatly improved compared to the extremely limited certainty provided by the “random point testing” associated with the typical thin-lift layer compaction using conventional compaction equipment.