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Glensanda Quarry UpdateIan Christie, drilling and blasting manager with BAM Ritchies, and DavidGibson, business development manager with BAM Ritchies, outline thelatest developments in drilling and blasting at the UK’s largest quarry

Glensanda Quarry, operated byAggregate Industries, is the largestgranite quarry in Europe and the largest

quarry in the UK. In 2008 Quarry Managementfeatured changes to the drilling and blasting

operations at the site, and now, some fouryears on, an update is timely.Before 2008, the site traditionally used in-

house drilling with shotfiring operationscarried out by Orica from an on-site bulk

emulsion manufacturing plant. Drillingoperations were carried out by two site-operated Ingersoll Rand DM-45E rigs drilling168mm diameter holes, together with fourECM 350 pneumatic rigs that were used forproduction and development blasting. A total of nine staff were employed, producing approximately 6 million tonnesper year.Today the quarry produces 7.5 million

tonnes of blasted rock per year (approximately150,000 tonnes per week), all of which mustbe suitable for loading by Caterpillar 992loading shovels. This represents a drillingrequirement of around 3,000m per week or150,000m per year.Since 2008, BAM Ritchies have been

providing the drilling and blasting service inthe quarry, producing about 7 million tonnesper annum, after Aggregate Industries soughtthe provision of a best-value, innovativeservice using the latest drilling and blastingtechniques.Since starting, a number of notable changes

have been introduced with far-reachingbenefits, including increased production, ‰

Drilling & Blasting

Glensanda, the UK’s largest quarry, produces 7.5 million tonnes of blasted rock each year

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reduced costs and a significantly reducedcarbon footprint, brought about by fuel-efficient drill rigs and higher unit productionoutputs.In addition, the use of modern rigs and

methods, based upon industry-leading riskassessments and procedures, is helpingthe company’s commitment to eliminateincidents and accidents. The newdevelopments and techniques cover allelements of the drilling and blastingoperations.

Surveying and faceprofilingSurveying and face profiling is carried outusing MDL’s Quarryman Pro with Quarry.4from Co-Ordinated Survey Systems. Lowcloud and heavy snow are common at thesite, with heavy cloud sometimes lasting fordays. This can have a massive impact onprofiling as a typical scan can take up to45min to complete due to the size of the facesbeing fired.However, future improvements in

technology and software will make this amuch quicker and efficient process throughthe use of the fast-scan feature on thelatest Quarryman Pro combined with

developments in the survey software. Thesedevelopments will allow profiles to be carriedout in less than 10min, thereby significantlyreducing time lost waiting for the cloud to lift.

DrillingAll of the drilling equipment previously usedon site has been decommissioned andreplaced. The primary resource nowcomprises two Atlas Copco L7 drill rigs, bothfitted with the COPROD system, Glensandabeing the only site in the UK to operate theCOPROD system on L7 rigs drilling with a102mm drill string. Both rigs are fitted withthe COP 4050-series rock drill that provides48kW of energy at a frequency of 50Hzthrough the COPROD drill string, whichcomprises an outer guide tube and inner drillsteel that carries the drill’s energy to the127mm bit.With the COPROD system the L7 is

approximately 30% more fuel efficient in adrilling shift compared with a standarddown-the-hole (DTH) machine of similarsize. Having an average penetration rate inexcess of 1.0m per minute, the L7 hasnearly twice the penetration rate of theDTH machines, making the fuel economy permetre even greater.

Each L7 is capable of drilling 350m in anormal shift drilling regulated benches ona varying staggered pattern, depending onthe local geology of the quarry. It is necessaryto present the blasted muckpile in a specificprofile allow it to be easily and safely workedby the loading shovels, and to ensure that thematerial ravels freely as it is dug.The site also operates an Atlas Copco

remote-control D9 rig fitted with a top-hammer. BAM Ritchies own and operate thelargest fleet of this kind of rig in the UK. TheD9 is used for both production anddevelopment blasting, and has the ability todrill in some of the most inaccessible areasof the quarry with little difficulty. The operatoris able always to safely operate the rigusing the remote-control unit, while the rigitself can be safely anchored using its ownbuilt-in winch.More recently a Sandvik DP1100i has

been introduced to the site, bringing furtherbenefits. These include: easy adjustment ofall parameter settings from the cabin;several factory-preset drilling parameters fordifferent rock conditions; operator tuning andstorage of optimal parameters for eachdrilling location; and an easy return to thepre-settings for drill bit rev/min, penetration

Since 2008, BAM Ritchies have provided the drilling and blasting service at Glensanda

Drilling & Blasting

rates and hole depth.Other benefits include: excellent torque

control for good rotation and good rockcontact, self-adjustment of power levelaccording to penetration rates, feed,percussion follow-up for maximumpenetration rates, and selectable auto-collaring. In addition, highly productiveoperation is available from day one as aresult of simulator-based operator training. This state-of-the-art drill rig has other

benefits such as low fuel consumption thatproduces 90 tonnes less CO2 at 6,700 enginehours than the previous similar rigs. Not onlydoes this reduce the effect on climate change, it also reduces costs to thecontractor, client and end customer.Safety is a crucial consideration and the

latest generation of rigs have FOPS/ROPScertified cabins that are: pressurized toexclude dust; offer clear visibility for theoperator; provide efficient filtration forincoming and recirculating air; and featureair-conditioning, cabin suspension toeliminate vibrations and an opening safetygrille for window cleaning.Other benefits include high-frequency

stabilizer rock bits, large fuel tanks and wide,powerful tracks.A comprehensive web-based reporting

system records site data includingproduction, hours, fuel consumption,condition and rig location, while service-requirement forecasting ensures that thecompany’s rigs are maintained in productivecondition to ensure client satisfaction.

BlastingThe site has its own bulk-emulsionmanufacturing plant which is supplied andoperated by Orica, who use an all-terrainbulk truck to deliver the product to theblast site. The current requirement isapproximately 1,500 tonnes of bulk emulsionper year.The site was one of the first in the UK to

introduce electronic initiation as the solemeans of initiating explosives. While thismeans of initiation is up to four times moreexpensive, the benefits in terms of blast ratio,fragmentation, pattern and control of throwoffer a much larger payback for both thecontractor and the client.The key to ongoing success is ensuring

that sufficient development work is carried

out in line with normal production, much ofwhich will only be accessible by the variablefleet of specialist rigs. These areas must nowbe blasted and opened up to allow productiondrilling and the future development of thequarry to take place. In the coming years itwill be necessary to blast the rock thatsurrounds Glensanda’s glory hole, while asecond shaft is being constructed.Investigation of ground vibration during

blasting will be used to ensure minimaldisruption to the glory hole and that nooversize material which could potentiallycause a blockage is allowed to fall back intothe shaft.

BenefitsAll of the drilling and blasting work nowcarried out at Glensanda Quarry is done byjust seven personnel. Jim MacDougall, BAMRitchies quarry engineer, commented: ‘Witha continually changing and increasinglydemanding production environment, it isessential that the drill and blast operationsadapt to the needs of the quarry. Staying ahead with advances in technologyand improvements within the industry is keyto the operation’s success.’ QM

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The introduction of a state-of-the-art Sandvik DP1100i drill rig has brought several benefits to the site