High-productivity, high-resolution 3D seismic surveys for open-cut coal operations

Summary

3D seismic is routinely used for structural characterisation for underground coal operations, however the implementation of this technology for shallow, open-cut resources has been limited. The perceived high cost of shallow 3D seismic has been one of the main factors holding it back. This paper will demonstrate that by adopting and adapting best practice technologies from the petroleum industry, 3D seismic is not only cost effective but also delivers higher confidence resource knowledge compared to traditional pattern grid structural and coal surface drilling. With higher resolution understanding of structure affecting the coal resource, the business can better predict and mitigate risks such as Geotechnical events, and minimise impacts to production with an improved mine plan.

A series of trial surveys were acquired over a range of geological settings, including variable thickness Tertiary basalt cover, multiple seams and very shallow target seams. Success of the 3D seismic technique in all of these trials validated the larger scale implementation at other open-cut mines. Next, through a process of iterative improvement of parameters and survey design, improvements in productivity and data resolution of these surveys were made to maximise value of information. The third step was to embed the subsurface knowledge obtained from seismic data into mine planning workflows and decisions. This work has already resulted in reductions in drilling and adjustments to geotechnical models.

Current work is focussing on further optimisation of the data acquisition, processing and interpretation workflows to ensure fit-for-purpose, long-lived information is delivered to the business. This includes revisiting and reprocessing legacy 3D datasets to harness advances in processing algorithms.

• coal
• 3D seismic
• open-cut mining
• structure