TROUBLESHOOTING CASE STUDIES:
At Westfield, near Aberdeen, a soft fruit grower had spent over £10,000 on a 100m borehole complete with lining and pump installation that was filling a reservoir at a very inadequate flow rate of 135 l/hr. A lot more water was needed so Geodivining was commissioned. The Geodivining survey located a clearly defined major fault in the migmatitic psammite and granite bedrock and an optimum location for a new borehole was identified. The new location was only 10m away from the original borehole, and when drilled to 75m, produced a sustainable yield of over 4,500 l/hr – a 33-fold higher yield than the original borehole 10m away.
Inverlair, Glen Spean
The water requirement in this case was quite small – about 900 l/hr – and, assuming this could be found at any conveniently accessible location, a drilling contractor had already drilled 3 boreholes, each more than 115m deep, and all of which were completely dry. A Geodivining survey was commissioned and delineated one clearly defined fracture zone in the bedrock beneath the site, assessed by Geodivining to have flowing water at 20 – 30m depth with a sustainable yield in excess of 1,500 l/hr. Two potential drilling locations were marked on this structure, and one was subsequently drilled to 30m producing a sustainable yield of 2,250 l/hr.. Had the Geodivining survey been commissioned first, the client would have saved in excess of £15,000 spent on 3 dry boreholes.
Brownrigg Farm, North Berwick
A potato farm in East Lothian, the driest district in Scotland, had a water requirement for irrigation, ideally in excess of 45,000 l/hr. 12 previous drilling attempts had been made, totalling over 1,500m by 4 different contractors over a number of years, and had failed to find any substantial water supplies in the thick volcanic rocks of the Garleton Hills Volcanic Formation. The best borehole had produced only 5,000 l/hr – an abundant supply for some clients but not nearly enough to irrigate hundreds of acres of potatoes.
The Geodivining survey revealed a few minor local structures and one major vertical fault line running right through the farm, which presented a 3m-wide linear target on the ground and was assessed by Geodivining to offer a sustainable yield in excess of 45,000 l/hr from about 90m. Subsequent drilling work on the exact location developed a yield of 54,000 l/hr from 105m with a strong artesian flow up to 15,000 l/hr in the winter months.
McEwen Potato Farms, Angus
This client has several farms in Angus, and had just drilled 4 unsuccessful boreholes on one farm before making a lucky strike with the fifth that yielded 45,000 l/hr. The drillers then moved on to Myreside and Priestfield Farms and drilled 5 more deep boreholes all to no avail. As a last resort, the drillers contacted Geodivining to see if we could come up with a successful solution.
The Geodivining survey confirmed 8 key intersection points that would be highly productive for yields exceeding 45,000 l/hr. One of them in particular was clearly better than the rest, offering a potential yield of 67,000 l/hr from a 120m borehole, and this one was selected for drilling. The client and drillers were understandably sceptical, particularly as this prime location was less than 30m away from a 105m borehole that had yielded only 4,000 l/hr, but they were willing to try one last time. Their scepticism converted to incredulity when drilling to 105m at this location yielded over 80,000 l/hr – 20 times more than the nearby failed borehole.
Geodivining was then asked to survey another of the client’s farms. After one drilling failure due to technical difficulties in unexpectedly deep running sand overlying the most promising intersection point, we relocated to the rig to another good source where, after spot-divining the whole area, I found the overburden to be at its thinnest with bedrock at about 15m depth, and an anticipated yield of at least 65,000 l/hr from a well-defined fault zone only 2-3m in width. The successful 100m borehole struck a high pressure artesian supply in excess of 72,000 l/hr, tested for over 100,000 l/hr by pumping. A subsequent survey of the client’s home farm secured another first-strike 90,000 l/hr yield. On these three farms, Geodivining converted the drillers’ success rate from 10% to 75% and improved the drilling productivity ten-fold, from less than 90 l/hr per metre drilled to 900 l/hr per metre drilled.
Hilton of Carslogie, Cupar
Another more recent example is the Geodivining Survey of Hilton of Carslogie near Cupar, Fife. The prognosis for high yield prospects was quite poor, what with close proximity to underlying volcanic rocks, a number of abandoned test boreholes, and no fewer than six known low-yielding boreholes on the farm. Four of these boreholes pumped collectively into a buffer tank provided barely enough water to run one irrigator and achieved poor seasonal sustainability. The Geodivining Survey revealed a previously unknown major fault zone running right through the farm and passing within 10m of the best of the low yield boreholes (see photo below). The existing borehole no.4 had a known depth of 77m and an estimated yield of 14,800 l/hr.
This location near borehole no.4 was the second of the two primary targets assessed from the Geodivining remote-sensory survey as likely to produce a sustainable yield well in excess of 45,000 l/hr, and the detailed assessment on site indicated a possible yield as high as 67,000 l/hr if it was drilled to a sufficient depth to fully intersect the source structure.
Once the exact location was marked a sequence of on-the-spot Geodivining measurements were made to establish a depth and yield profile confirming this prognosis for drilling up to 120m depth. Drilling to 135m subsequently proved this was another high yielding successful borehole with measured flow off the drill well in excess of 60,000 l/hr and excellent sustainability.
View of the Geodivining Location 2 at Hilton of Carslogie (surveyed 2010), marking the centre of the
fault zone (shaded blue) with the existing wellhead of Borehole 4 a few metres away to the left.