High-pressure portable pumping in deep hole excavations
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0262 1762/04 © 2004 Elsevier Ltd. All rights reserved WORLD PUMPS August 2004 T he old phrase ‘two heads are better then one’ may be fine when trying to generate new ideas, but in pumping terms, using two pumps in line to create sufficient discharge head has always had its share of problems. Unfortunately, this was one of the few options available to quarry engineers faced with removing water from deep hole excavations. Take for example, a gold mine in Australia faced with moving water at a flow of over 250 m 3 /hr with a total dynamic head of 150 m from a deep hole excavation. Initially, pumps in tandem (primary and booster) were being used to move the water to the delivery point. As with any tandem system, balancing the flow of the primary pump into the booster pump is a delicate process. In addition, the potential for equipment breakdown is doubled when two pumps are used in a single system. Another pumping option utilized was a single stage ISO pump that operated at the far left of the pump curve (low flow, high resistance) causing discharge cavitation issues and shortening the life expectancy of the pump. In both pumping scenarios, closed impellers were used making solids handling an added concern. What was needed was a portable pump that was built for the construction/mining market and was capable of producing high discharge head. Enter Godwin Pumps Limited of Quenington, UK. Godwin had already developed a complete line of high head pumps for the mining and industrial markets. When contacted by the Austalian gold mine about the dewatering application, the first thought was to tackle it with an existing Godwin High Lift (HL) pump. Upon further study of the application, however, the duty point (flow and head) didn’t seem to fit any existing pump curve at a ‘best efficiency point’ (BEP). The gold mine application was projected to run on a continuous basis. Therefore, the pump chosen for the application needed to function in the BEP on the curve, to help reduce mechanical failures due to extreme operating conditions. The answer was to go to the proverbial drawing board and design something new. New Pumps In 2001, research at Godwin Pumps began on a new design of high head pumps with delivery pressures exceeding anything currently available in the portable pump market. With the Australian gold mine application in mind, engineers at Godwin initially considered a two-stage impeller design, improving on the total dynamic head capabilities of the HL6 T/S2 pump. However early on in the design phase, consideration was given to a single- stage open impeller that would provide better solids handling capabilities. As Dave Braithwaite, Godwin’s Director of Engineering, explains: “The benefits High-pressure portable pumping in deep hole excavations Dewatering deep hole excavations in aging quarries leaves mining engineers with few portable pumping options, none of them good. Traditionally, the choice comes down to tandem pumping or running a single pump at a severe duty point. The development of a new generation of portable diesel-powered high-pressure pumps could provide the solution. Peter Snow, training manager at Godwin Pumps, explains. feature pumping at high pressures Look closely… at the bottom of the photo is a Godwin Dri-Prime® model HL160M portable pump that is dewatering a gold mine in Kalgoolie, Australia. Look again to see the delivery line winding up the haul road and then up the face of the mine to a discharge point. Flow rate achieved is 252 m 3 /hr at a delivery head of 152 m. 28
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Transcript of High-pressure portable pumping in deep hole excavations
0262 1762/04 © 2004 Elsevier Ltd. All rights reserved WORLD PUMPS August 2004
The old phrase ‘two heads arebetter then one’ may be finewhen trying to generate new
ideas, but in pumping terms, using twopumps in line to create sufficientdischarge head has always had its shareof problems. Unfortunately, this wasone of the few options available toquarry engineers faced with removingwater from deep hole excavations.
Take for example, a gold mine inAustralia faced with moving water at aflow of over 250 m3/hr with a totaldynamic head of 150 m from a deephole excavation. Initially, pumps intandem (primary and booster) werebeing used to move the water to thedelivery point. As with any tandemsystem, balancing the flow of theprimary pump into the booster pump isa delicate process. In addition, thepotential for equipment breakdown isdoubled when two pumps are used in asingle system. Another pumpingoption utilized was a single stage ISOpump that operated at the far left of thepump curve (low flow, high resistance)causing discharge cavitation issues andshortening the life expectancy of thepump. In both pumping scenarios,closed impellers were used makingsolids handling an added concern.What was needed was a portable pumpthat was built for theconstruction/mining market and wascapable of producing high dischargehead.
Enter Godwin Pumps Limited ofQuenington, UK. Godwin had alreadydeveloped a complete line of high headpumps for the mining and industrial
markets. When contacted by theAustalian gold mine about thedewatering application, the firstthought was to tackle it with anexisting Godwin High Lift (HL) pump.Upon further study of the application,however, the duty point (flow andhead) didn’t seem to fit any existingpump curve at a ‘best efficiency point’(BEP). The gold mine application wasprojected to run on a continuous basis.Therefore, the pump chosen for theapplication needed to function in theBEP on the curve, to help reducemechanical failures due to extremeoperating conditions. The answer wasto go to the proverbial drawing boardand design something new.
New Pumps
In 2001, research at Godwin Pumpsbegan on a new design of high headpumps with delivery pressuresexceeding anything currently availablein the portable pump market. Withthe Australian gold mine applicationin mind, engineers at Godwin initiallyconsidered a two-stage impeller design,improving on the total dynamic headcapabilities of the HL6 T/S2 pump.However early on in the design phase,consideration was given to a single-stage open impeller that would providebetter solids handling capabilities. AsDave Braithwaite, Godwin’s Directorof Engineering, explains: “The benefits
High-pressure portable pumpingin deep hole excavations
Dewatering deep hole excavations in aging quarries leaves mining engineers with fewportable pumping options, none of them good. Traditionally, the choice comes down totandem pumping or running a single pump at a severe duty point. The development of anew generation of portable diesel-powered high-pressure pumps could provide thesolution. Peter Snow, training manager at Godwin Pumps, explains.
f e a t u r e pumping at h igh pressures
Look closely… at the bottom of the photo is aGodwin Dri-Prime® model HL160M portablepump that is dewatering a gold mine in Kalgoolie,Australia. Look again to see the delivery linewinding up the haul road and then up the face ofthe mine to a discharge point. Flow rate achievedis 252 m3/hr at a delivery head of 152 m.
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WORLD PUMPS August 2004 www.worldpumps.com
of a single-stage impeller designinclude less bearing stress, shorteroverhang of impeller to shaft andbetter overall stability.” The challengewas to achieve the high delivery headswith the single-stage impeller.
Through some creative engineering, anew impeller design emerged with adiameter of a whopping 508 mm. Apump volute was forged to house theimpeller and the resulting prototypewas mated to an existing bearingbracket assembly borrowed from theGodwin HL250M pumpset. Thus, theHL125M was born with a 150 mmsuction flange and 100 mm dischargeflange.
Spring of 2002 brought the first tests ofthe new HL125EHH (Extra HighHead) pump. Godwin’s engineers hadhoped for delivery head to be in the180 m range with flows to 310 m3/hr.To their utter surprise and delight, thepump achieved the anticipateddelivery head and in addition it wascapable of reaching flows in excess of400 m3/hr, well above what had beenexpected. This brought about acurious dilemma. The pump wasdesigned with a 100 mm dischargeflange connection, but the flowproduction of the HL125EHHwarranted a larger connection (150mm).
The end result was that theHL125EHH ultimately became twopumps: (1) the HL130M [150 mm x100 mm] and (2) the HL160M [200mm x 150 mm]. The original impellerdesign was fitted into a newly forgedvolute with 200 mm x 150 mm flangeconnections and powered by aCaterpillar C-15 Tier 2 compliantdiesel engine. The flow production ofthe HL160M pump far exceededanything that Godwin engineers hadexpected.
With the finishing touches put on theHL160M design, attention returned towhat now had become the HL130M(150 mm x 100 mm) pump. Wantingto reduce the power requirements ofthe HL130M, Godwin engineers faceda decision – trim the impeller diameterto reduce the head; or decrease the
width of the impeller to reduce flowcapabilities. The original goal of thepump was to create discharge head, sothe decision was made to reduce the width of the impeller, thereby reducing the flow capabilities.Testing on the HL130M ensued,powered by a Caterpillar C-9 dieselengine, with heads reaching 180 m andflow approaching 340 m3/hr.
All that remained was a field test of thepumps under actual site conditions.The gold mines in Kalgoolie,Australia, offered the perfectopportunity to put the newly designedpumps to work. Once on site, theprocess of positioning the pump andinstalling the suction and dischargelines began. When the piping systemwas in place, the HL130M pumps were started and testing began. The resulting production was 252 m3/hr at 152 m of total dynamichead.
The Caterpillar C-9 diesel engine wasturning at 2,090 rpm. Vibration was ata minimum and the system workedsuccessfully. The new HL130M hadpassed its first test. Others would soonfollow.
Scottish coal mine
A coal mine in Glasgow, Scotland,became the next field test for the newhigh head portable pump. The Scottishmine had been struggling withdewatering issues as the excavationgrew deeper and deeper. GodwinPumps was contacted through theirUK distributor, SLD Pumps, to providea pump to achieve 230 m3/hr at 130 mof total dynamic head. Due to thechanging excavation patterns, thepump system would need to be movedfrom place to place in the quarry as coalmine production continued. Anextremely high head portable pumpwas exactly what was needed.
Godwin engineers chose the HL160Mto tackle the application, whichincluded a 700 m run of discharge pipewith a vertical elevation difference of80 m from the pump to the deliverypoint. The 200 mm inlet by 150 mmoutlet HL160M pump was installedusing twin 150 mm discharge lines toachieve the required flow. Afterplotting a system curve the decisionwas made to run the application at1,600 revolutions per minute (rpm).Dewatering began at the coal mine
f e a t u r e pumping at h igh pressures
The heart of the beast – the massive 508 mm impeller is the heart and soul of the new HL130M and HL160M Godwinhigh head pumps. A single impeller is now delivering heads to 183 m with flows up to 350 m3/hr.
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www.worldpumps.com WORLD PUMPS August 2004
on 30 June 2003 and continues to the present.
Since those first installations of theHL130M and HL160M pumps,numerous applications have followedin the United States and around theworld. To take another old saying‘Build it and they will come’ has quite literally come true in Godwin’s
case as international customers haveselected the company’s new pumps.The HL130M and HL160M modelshave now been installed on some of the most challenging high headapplications ever seen in the portable pumping market and areoperating successfully, offering newchoices to mining engineers aroundthe globe. ■
CONTACT
John Miller Sales Director Godwin Pumps Ltd, Quenington,Cirencester, Gloucestershire,GL7 5BX, UK. Tel: +44 1285 750 271 Fax: +44 1285 750 352E-mail: [email protected]
f e a t u r e pumping at h igh pressures
Left: High head portable pumping reaches a new level with the advent of the Godwin Dri-Prime® HL130M and HL160M pumps. Pictured left is the HL160M Dri-Prime® single stage high head pump, which can achieve heads to 183 m. Right: The system curve for the HL160M Dri-Prime® pump application at GM Mining in Glasgow, Scotland.
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