Although there are still quite a few underground miners today, the most of opal is mined using heavy earth-moving machinery, operated by individuals, partnerships or family run businesses, whose love for finding these beautiful gems has turned into a vocation, fueled by passion, elbow grease and diesel!
By and large all attempts to mine opal by floated companies has ended in insolvency and tears, as this “top heavy” model is too costly to operate and generally lacks the multi-skilled, lean operations that are driven by passion rather than risk taken by shareholders wallets.
Opal Mining and the Environment
All opal mining and exploration, be it underground or open-cut, is regulated under the Codes of Environmental Compliance with strict codes pertaining to rehabilitation of the grounds to pre-mining land-forms.
All mining tenure holders are registered by the Department of Environment as "Suitable Operators".
Native Title and Cultural Heritage
Opal Miners must also undertake Cultural Heritage Protocols by either having areas of proposed disturbance on a mining or exploration site surveyed by the traditional land owners/ claimants and/or utilize the Gazetted "Duty of Care" guidelines, of the Aboriginal Cultural Heritage Act, Qld.
The QOMA and Opal mining Industry are supportive of preserving the Cultural Heritage and "Native Title Rights and Interests," of Aboriginal Peoples.
QOMA demonstrates this by its active participation in facilitating negotiations for Cultural Heritage Agreements for QOMA Opal mining members and to date the QOMA has had a 100% agreement achievement rate, which ensures mutually beneficial outcomes for the Traditional Owners & Claimants and the Opal Miners.
Duty of Care Guidelines (PDF)
New techniques for Opal Exploration
Whilst visual prospecting and drilling still seems to be the main exploration tools for finding new opal deposits, as they are tried and true, there is emerging exploration techniques including geo-chemical mapping and Ground Penetrating Radar (GPR) and drone photography, which are proving to be quite handy new tools for opal exploration and mining.
Ground Penetrating Radar
Ground Penetrating Radar (GPR) has been around for a while and the technology has been improving.
From the early days which were (and still are in some instances) single channel GPR’s, with simple black and white graphics on the displays, to the current GPR which can now utilise multi –wavelength (albeit the penetration is not as deep) with colour monitors and programs which help decipher the signals on the screen.
GPR in opal exploration is still in the early stages, but is a low impact form of prospecting and exploration which is equally important in "writing off dead ground" as it is in finding and locating potential ground for mechanical exploring.
The cost benefit of this tool is two fold as GPR can save on excavating holes which are less likely to produce opal or boulders, which in itself is a saving of both time and money, and can increase the chances by delineating areas with higher potential, as GPR can readily identifying faults slips and slides and sub strata layers and sometimes even the boulder levels, albeit harder to determine when the boulders are situated in clayiferous ground as GPR reflects more from the clay interface which can sometimes mask a boulder level.
Whilst GPR won’t tell you if there’s actually opal in the boulders, if your surrounding ground is generally opalised then there is a fighting chance that there is potential in areas tested which produce ironstone levels which can host opal.
The cost of GPR technology is one of the most limiting factors but the price is coming down, also then knowing what one is doing with the technology is a challenge, but the more you use them the more proficient you become, certainly the younger generations will benefit more from this technology as opal exploration and mining progresses into the future.
Drones are becoming more useful as this technology becomes more affordable.
Whilst they are easy (particularly for the inexperienced) to “crash and burn” the drones are a lot more stable and accessible than ever before and provide good detail of landscape in real time which can also be downloaded to computer for further and more detailed inspection.
Whilst satellite imagery is improving, drones provide an “Extreme Close Up” view of a limited area (due to battery life) which can provide a better oversight of an area for potential areas for prospecting, exploration and mining.