Safe drilling investigation of coal and mine workings
Coal Investigation. Need a safe, environmentally friendly and cost effective drilling investigation for coal and mine workings? Worried about the cost and the mess? Let Geoinvestigate quote for your coal drilling, coal mine drilling or mine working investigation.
Geoinvestigate Microdrill does it “FASTER, CHEAPER, NICER and NEATER”.
Drilling boreholes remains the only certain way of proving whether or not mine workings and mine shaft hazards really exist beneath a property. With the recent introduction of fast, small, lightweight drill rigs like Geoinvestigate Microdrill untidy and messy drill sites can now be avoided. Microdrilling is also less expense than big rig drilling because it requires less operators, less equipment and less drill water. Geoinvestigate Microdrilling is faster, safer and more environmentally friendly than conventional drilling. It’s also cheaper.
Because of its much smaller size Geoinvestigate Microdrill can get into places other drills can’t reach – through narrow gates and doorways into gardens and backyards and side alleys. Microdrill can even drill holes under buildings.
This is what coal looks like when its encountered during a Geoinvestigate Microdrilling investigation.
The drill water returning up the hole to surface is black. Either the coal seam is intact and has been left unmined or unworked at this location or it is a pillar/column of coal left in place underground by miners many years ago to support the roof of the working. However because coal was missing in the 2nd and 3rd holes and the ground was broken and voided where the coal should have been it was possible to establish in this instance that the coal seam had probably been extracted by the room and pillar method.
In most built up areas in the UK only drilling with water flush is safe and the Coal Authority won’t issue a drill license for anything else but water. This is because water flush is the safest way to drill coal and mine workings. Mud though safe is too messy.
Rarely to day is air drilling permitted in urban areas and in proximity to occupied buildings, offices and homes. This is not only because this method could cause explosion it also releases very large volumes of compressed drill air underground displacing large volumes of potentially toxic and flammable gases which could travel to surface along fractures in the rock, mine shafts, geological faults and even old boreholes.
Not only is Geoinvestigate Microdrill very much safer than air drilling it is also much safer than air mist drilling because with mist drilling large volumes of gas are still pumped into mine workings with the attendant risk of displacing toxic and explosive gases which may reach the surface entering buildings and homes with catastrophic results.
Typically Geoinvestigate Microdrill uses around 500 litres or 0.5 cubic metres of water to drill a hole from start to finish – a mere “thimble full” compared to other drilling techniques. Because of this Microdrills small volume water injection water drilling system is safer.
Because of the risk from gases created and released during coal and mine working drilling gas monitoring is carried out during drilling. At the end of drilling boreholes are sealed to prevent a pathway between the workings and the surface.
A coal drilling permit is required from the UK Coal Authority before drilling or any or other intrusive investigation excavation is carried out at a site. Geoinvestigate regularly assist developers to obtain CA drill permits or we can include the obtaining a permit within our quote. Because Geoinvestigate Microdrill uses only the SAFEST small volume water injection method to drill obtaining a drill permit through us from the Coal Authority is straightforward and rarely a problem.
In 2015 Geoinvestigate Microdrill was successfully demoed to the UK Coal Authority and has subsequently completed over 400 coal drilling investigations across the UK from Swansea to Bristol, Birmingham to Nottingham and Newcastle to Glasgow for homeowners, developers, builders and consulting firms.
Unlike many borehole contractors Geoinvestigate’s coal and mine working experts can provide a follow-up technical report on the outcome of the drilling investigations so you don’t have the hassle of finding a geologist to provide a 2nd interpretative report at additional cost.
In mineworking investigation 2 drill holes are better than 1 and 3 holes are even better. This simplified model of room-and-pillar mining shown above aka pillar & stall and stoop and room (Scotland) explains this. A room is a mine opening where the coal has been removed between coal pillars left in place to support the roof. With only 1 hole there is 50% chance of encountering a pillar and being mislead into assuming that the coal seam is both intact and unmined. Clearly from the model this would would be a dangerous mistake to make. With 2 or more holes the likelihood of misinterpreting coal mining legacy reduces. 3 drill holes allows the orientation and dip or inclination of the coal seam and workings to be established in 3 dimensions.
Simply the more boreholes you drill the more confidence there is in the interpretation of the mining situation. While most larger drilling rigs struggle to complete 1 hole in a day Geoinvestigate’s new Microdrill can achieve 3 or more holes depending on depth.
More drilling allows identification of the most cost effective solution for stabilising a site and making it safe.
We provide cost effective coal and general mine drilling services across the country. We also carry out drilling investigations to find mine workings and sinkholes in Chalk, Limestone, Gypsum, Ironstone and Sandstone. The following image shows a Geoinvestigate Microdrill investigation near Hemel Hempstead of possible Chalk Denehole mine workings.
If you need to drill into coal and mine workings or you have had a CMRA (Coal Mining Risk Assessment) done and you need to drill before you start building contact Geoinvestigate and get a free no obligation quote.