Traditional working practices and techniques for assessing rock burdens provide only rough estimates of rock face burdens and mean blasting has been associated with a poor health and safety record through dangerous fly-rock incidents and varying efficiency.

During the last 20 years increasingly more efficient technologies have been developed by eye-safe laser measurement specialist, Measurement Devices Ltd (MDL) based on an in-depth understanding of surveying for the quarrying and mining industries and the vast potential of laser technology.

This year York-based MDL launched the Quarryman Pro, its latest reflectorless rock profile and 3D laser scanning system used by many major surface mine and quarry operators worldwide.

Demand for the technology is being driven by UK quarrying regulations requiring that the weakest areas of burden must be detected, a natural desire to reduce fly-rock incidents and, in increasingly competitive global markets, to improve operational and cost efficiency.

MDL’s latest Quarryman Pro allows high-speed 3D scanning to determine the rock-face geometry with minimum training and skill. Face Pro 3D software is fully featured, outputs all the required burden geometry data for the blasting engineer and is in line with the UK HSE regulations.

The Quarryman Pro, which won a Health and Safety Executive merit award this summer following a Designing for Safety Competition jointly hosted by The Institute of Quarrying and the Quarry Products Association, has additional applications including stockpile volume measurement, 3D mapping of entire mine sites as well as 3D rock profiling for determining rock-face geometry and blast-hole burdens.

The fully-automatic £15,000 system has a reflectorless range of up to 600m and scans rock faces measuring and recording up to 250 points a second on a compact flash memory card which is inserted into the instrument and eliminates the need for external field recorders or computers.

An increase in the number of data points the Quarryman Pro can record while scanning gives operators a more detailed 3D image of the rock face than was previously available. The Quarryman Pro can also be used as a traditional total station, allowing resections, traverses and single shots to be taken.

This makes it easy to join multiple scans from different instrument set-up points, thereby creating comprehensive, all-round views without hidden shadows.

Sales engineer in MDL’s Laser Systems Division, Anthony Comber, says: “Health and safety are paramount but are not the only benefit. Better understanding of the burden leads to more cost-effective use of explosives and a more controlled, accurate blast.

“Being able to judge the correct level of explosives usually leads to a reduction in the volume required. This, in turn, reduces excessive ground vibration which can create public relations problems with nearby homes and businesses, environmental problems and, in extreme cases, damage to property.

“Stockpiles are a major asset and being able to accurately measure their volume helps business planning.”

A large Irish aggregate quarry which started using MDL’s Quarryman equipment systems reported 150 per cent extra production hours, 75 per cent reduction in secondary breakage, amounting to Euro 250,000 in first year; 20 per cent increase in crusher throughput, 75 per cent blast reduction, 20 per cent saving in explosives 10 per cent saving in drilling costs, 10 per cent saving in maintenance and a 90 per cent reduction in environmental complaints.

To provide a total solution, MDL has also developed two Boretrak systems so quarrying professionals can get an exact understanding of `as-drilled’ borehole deviation, and the true burden, before blasting.

The two Seven Thousand Pound (UK) systems are the Rodded Boretrak & the Cabled Boretrak. The Rodded Boretrak is lowered on fiberglass rods, is non- magnetic and can be used in all types of rock and flooded holes as well as in areas of ferrous materials and in hole casings, while the Cabled Boretrak is lowered on its own cable and uses a digital compass to establish its orientation.

Both systems feature rugged probes containing a dual-axis tilt sensor which calculates borehole deviation from a series of sensor readings taken at fixed intervals down the borehole.

01/11/07 02:02pm