UNITED KINGDOM UK’s largest listed water company looks to double capacity for its Kerridge facility 03 JAMAICA When we were up in the Jamaican mountains 04 GABON Thumbs up for problem solving in Gabon, Central Africa 05 gLOBAL geOdATA neWs issUe 05 | sUMMeR 2019 Ireland ROBeRTsOn geO’s fLeeT of service logging vehicles are fully customised and equipped ready to go whatever the location or application, seen here at a new deep mine development at Boliden Tara Mines.
Transcript
UNITED KINGDOMUK’s largest listed water company looksto double capacity for its Kerridge facility
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JAMAICAWhen we were up in the Jamaicanmountains
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GABONThumbs up for problem solving in Gabon,Central Africa
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globAl geodATA neWs issUe 05 | sUMMeR 2019
IrelandRobeRTson geo’s fleeT of service logging vehiclesare fully customised and equipped ready to gowhatever the location or application, seen here at anew deep mine development at boliden Tara Mines.
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ORE HAS BEEN extracted there since1977 and it is estimated that morethan 85 million tonnes have beenmined since this time. Boliden ABthe Swedish smelting and miningcorporate giant acquired the TaraMine in 2006.In 2018 some 2200 ktonnes of orewas processed into metalconcentrates containing zinc, lead
and silver. In May of the same year anew joint venture was announcedwith Minco Ireland to extract a newarea of deposits, making Tara Minesone of the world’s deepest mineswith fresh ore located up to 1.9kmbelow the surface.
As part of the development of thenew deep mine sector Robertson Geohas been contracted to log a pilot airshaft down to 250m.
The new RGeo-eye 4 core borehole
camera has been deployed toinvestigate borehole integrity at250m. It has provided excellent visualdefinition of the shaft. After thecamera, probes were deployed togenerate a composite log for thestructural integrity and continuousdiameter of the borehole shaft. Theprobes used were AcousticTeleviewer (HRAT), 3 Arm Caliper,Triple Sonic and TemperatureConductivity.
Logging on location at
euroPe’sBiGGest
zinC Mine
Image shows borehole camera transmissionat 250.68m.
Tara Mines of Navan, County Meath,Ireland is in the top ten of the world’s
largest zinc mines.
3www.robertson-geo.com
RobeRTson geo cUsToMeRgeotechnics is conducting theground investigation on behalf ofMott Macdonald, the globalengineering, Management anddevelopment company.three of the eight boreholes that arescheduled for drilling have beenlogged to produce a subsurfaceteleviewer survey. one borehole gaveexcellent optical output from thehigh resolution optical televiewer(hi-oPtV) probe and the other twogave excellent data when the hi-oPtV and the high resolutionacoustic televiewer (hrat) probedata was combined.
the boreholes range from 20m –30m deep of 146mm diameter andare cased off at between 1 and 2m.
seATTle’s TRiniTy pARish church wasestablished in 1865, it is a historic building andwas added to the national Register of historicplaces in 1991.a major development is taking place in the Churchgrounds, announced in 2018 by australian developerCaydon. the historic Church will remain but otherbuildings on the site will make way for a high-rise 28storey tower of 200 plus condominiums.
Jorge ramirez of robertson Geo inc and Meron okbayMs of customer insitu engineering of snohomish,Washington state commissioned a new Ps logger suiteof equipment at the 100ft pilot borehole for subsurfaceinvestigation in the trinity Church grounds off 8thavenue.
the Ps logger was successfully deployed with dataacquired from 87ft through 7.5ft. a mini winch (175ftcapability) and the Micrologger2 surface interfacesystem, together with Winlogger the Ms Windows based operating system was part of the commissioningand training.
PS LOGGER INseattle
Mr. Meron Okbay MS of Insitu Engineering accessing data from the PSLogger deployed into the pilot borehole at Trinity Parish Church.
UK’s largest listed water company looks toDOUBLE THE CAPACITY
FOR ITS KERRIDGE FACILITY
The initial data acquisition was completed by a Robertson Geo Service team, using the latest addition to itsfleet of logging vehicles, a customised Toyota 4x4 Land Cruiser with its installation of mobile dataacquisition and winch deployment surface equipment.
The United Utilities facility has four megalitres of processed potable water in a coveredreservoir at Kerridge overlooking Macclesfield, cheshire UK.
it is looking to replicate the existing capacity within adjacent land by a further four megalitres.
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JAMAIC ANmountains
When we were up in the
This sTReTch of motorway connects theJamaican capital, Kingston, to Mandeville,a bauxite mining town in the eastern partof the island.
Robertson geo was contracted toundertake the downhole opticalteleviewer and natural gamma logging ona mountainous section of the thenproposed highway 2000 project.
This section of the route had a subsurfaceclay band that posed some engineeringconcerns due to the nature of themountainous landscape; the clay bandcould pose a landslip risk.
The data acquired by Robertson geo was used to help map the clay band anddetermine the required foundations and anchoring required to secure themountainside for the development of the highway.
Bouygues Travaux Publics was appointed to build the Highway 2000 motorway,including duplication and upgrading to motorway standard of a 14-km-long stretch of the existing Dyke Road.
www.robertson-geo.com
Why do major civil engineeringprojects routinely deploy theRobertson Geo PS Logger
probe for determination of soiland rock strength?
Robertson Geo is a global market leader in slim-hole logging instrumentation with
in-house design and manufacturing facilitiesand offers a proven logging service worldwide.
SOUNDPRACTICE MEANS
SOUNDECONOMICSThe Robertson Geo PS Logger Probe
PS Logger probe deployed in an offshore location (Hong Kong).
www.robertson-geo.com
oRiginAlly developed by RobertsonGeo parent company OYO Corporation inthe 1970’s to provide a full waveform toolthat would produce reliable P and S wavevelocity measurements in unconsolidatedmaterials and rock formations at depth.The initial application was microzonation,to characterise earthquake prone zoneswith respect to geological and geophysicalcharacteristics such as ground shaking,liquefaction susceptibility, landslide, rockfall hazard and earthquake-relatedflooding, so that seismic hazards within thearea could be identified.
So successful was the probe that it soongained acceptance in the civil engineeringarena, firstly in Japan and Asia, then USAin the 1980’s and subsequently in Europe.The development and manufacture of theprobe was continued by Robertson Geo in2007 where it has remained a marketleader, especially in the burgeoningoffshore wind farm market.
The PS Logger system is offered worldwide
as a turnkey service, for long-term andshort-term rental, or for outright purchase.It is also plug compatible with the full rangeof Robertson Geo slim hole probes, that arecalibrated and issued with a conformancecertificate prior to mobilisation.
HOW THE PS LOGGER WORKSThe PS Logger is a full waveform acousticprobe, designed to measure compressionaland shear wave velocities in soils and rockformations. It operates using indirectexcitation rather than mode conversion asin a conventional sonic. It is capable ofacquiring high-resolution P and S wavedata in borehole depths of up to 600m.
It contains a unique design of powerfulhammer source and two receivers,separated by acoustic damping tubes. Toacquire data, the probe is stopped at therequired depth and the source is firedunder surface command. Firing causes a
solenoid-operated shuttle aligned acrossthe borehole axis to strike plates onopposite sides of the probe in turn, settingup a pressure doublet in the surroundingfluid. The resultant fluid motion produces atube wave at the borehole wall withvelocity close to the shear velocity of theformation together with a compressionalwave. As the waves propagate parallel tothe borehole axis, they set upcorresponding fluid movements that aredetected by the two-receiver combination(neutral-buoyancy 3D hydrophone for P waves and horizontally alignedgeophone for S waves), allowing the wavevelocities to be directly measured. Thefacility to stack multiple shots and filter thedata as in normal seismic data acquisitionis included in the operating software.
KEY BENEFITSThe PS Logger works in a single fluid filledborehole in contrast to cross- holemethods that usually require two or more
The ps logger probe measures p (compression) and s (shear) wave velocities in a single borehole without theneed for external energy sources, making it simple and quick to deploy and therefore cost effective, especiallywhen compared to alternative methods. When combined with bulk density values (from a density log or fromcore sample tests) small strain moduli (young’s, shear and bulk) can be calculated using simple formulae.
Cased and ready to go:the PS Logger is proven with data acquired from thousands of boreholesworldwide, often in the harshest ofoffshore applications
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specially prepared boreholes. The methodworks in open or grouted plastic casedboreholes and borehole muds generally donot need to be flushed prior to logging,without compromising borehole stability.The PS Logger is largely unaffected bypath affects which can be problematic forcross-hole methods.
With an integral powerful source, energydelivery is constant throughout the extentof the borehole, independent of boreholedepth, giving reliable velocitymeasurement in hard rock and the slowestof formations. The high vertical resolution(0.5m typical) allows for measurement ofthin layers and is not affected by highvelocity layers above low velocity layers.As no external source is required thismakes the system ideal for workingoffshore on barges, jack-up platforms anddrill ships.
As the probe is suspended in the boreholeno clamping to the borehole wall isrequired allowing faster acquisition. The PS logging can be conducted at the end ofthe drilling alongside any of the full rangeof conventional logging probes thatRobertson Geo offers.
The propagated waves are measured in thevertical plane providing the most usefulinformation in anisotropic formations.
When combined with bulk density valuesthe PS Logger provides a continuousstrength profile, especially important whenhard layers are encountered and CPTmethods ‘refuse’.
The relatively high frequency of the source,when compared to other methods, meansthat good data can usually be obtained invery noisy environments. On drill shipswhere engines, DP thrusters, generatorsand ancillary equipment contribute to theambient noise this is very important. Thereversed polarity shear wavemeasurements provide unambiguousidentification of shear wave arrivals.
APPLICATIONS ANDENVIRONMENTSRobertson Geo has been regularlydeploying the PS Logger throughout theworld since 2008, especially for offshoreprojects where alternative methods areimpractical. The list of projects includeswind farms, bridges, port extensions, oiland gas sub-surface infrastructure andnuclear power plants.
The UK is a world leader in thedevelopment of offshore wind farms. Rockstrength information is key to engineersdesigning foundations for the massivestructures which support the latest
generation of turbines. Operating fromjack-up platforms or from drill ships,marine resistant technology developed byRobertson Geo has allowed the PS Loggerto be routinely deployed. The list of windfarms is extensive but includes Seagreen,Dudgeon, Hornsea, Moray East and NeartNa Gaoithe in the UK as well as those inGermany, France, Belgium, Denmark andthe USA.
PS Loggers have also seen action on manyof the UK’s largest infrastructure projectsincluding Wylfa, Sizewell B, Oldbury andBradwell nuclear power stations, HS2,Lower Thames Crossing and A303Stonehenge bypass, in addition to manyother major civil engineering projects.However, the ease of deployment and costeffectiveness of the technology meansaffordability for even the smallest ofprojects.
DRILLING MATTERSBorehole conditions play a big part in dataquality and that is where the drillingpersonnel should be involved. Rotarydrilled boreholes always provide the bestdata (low rugosity). The PS Logger canproduce good data in boreholes from65mm to 400mm with the optimum rangebeing from 75mm to 200mm. Inclined
The assembled probe:PS logging is unique in offering high resolution seismic measurements from a single borehole up to 600m depth.
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boreholes can also be logged providing thetilt is no more than 30⁰ from vertical.
Where borehole stability is an issue thelogging is often split into separate runswhereby the drill string is retrieved instages. To minimise possible loss of data,close liaison with the drillers, geologistsand geotechnical personnel is required toconfirm where the potentially unstablelayers are (e.g. gravel beds). A shootingplan can then be made whereby the drillstring can be withdrawn in stages toprovide some open borehole whileproviding protection for the problematiczones.
Due to the PS Logger’s tolerance toborehole muds, there is little or nopreparation required on the borehole.Polymer or Bentonite based muds can beextremely viscous with the limiting factorbeing the buoyancy of the probe. Wherethe use of thick mud fails to providesufficient borehole stability the boreholecan be plastic lined and grouted. Aspecification for the grouting can besupplied.
PROCESSINGFull waveforms are recorded digitally atacquisition time across 6 channels (P wave, S wave left & S wave right at thenear and far receivers) at a predeterminedsample rate as low as 2.5µsec. The samplerate is carefully selected to be as small aspossible to provide the best resolution buthigh enough to capture the arrivals withinthe listening window. Low pass filters canbe applied at acquisition time and digitalfilters can be applied during or postacquisition.
Using the acquisition software, thewaveforms can be displayed, scaled andfiltered to allow for the picking of the firstarrivals at each receiver. Automatedpicking is available but in most cases thearrivals are picked manually byexperienced engineers. While the P wavearrivals are generally simple to pick, the S waves with their typically slow onset andpossible superposition over the decaying P waves benefit from an experienced eye
to avoid ‘cycle skipping’. From the receiverseparation (1 metre) and the arrival timesthe velocities are automatically calculated.
Once the arrival times and velocities havebeen determined, the data is opened in asecond program (also supplied with all PS logger systems) that creates andmanipulates logs of the data. If a bulkdensity profile by depth is available it canbe combined with velocities to give thesmall strain moduli, Young’s, Shear andBulk and Poisson’s ratio. Finally, all datacan be outputted in industry standard LAS format.
Robertson Geo Logging Servicesdepartment offer a 3rd party processingservice for clients renting or buyingsystems.
From unconsolidated soils to thehardest of rocks, the PS logger gives proven results.
Simplicity of deployment combined with aminimum of borehole preparation and theability to obtain high quality velocity datain unconsolidated formations and hardrocks make the PS Logger a soundeconomic choice for Geotechnical and CivilEngineers investigating rock strength.
Example of single wave trace output.
Example of basic velocity logs.
Example of full probe data logs.
SMALL STRAIN LOGS:
Graham Comberlogging services Manager, Robertson geo
5www.robertson-geo.com
Continuing subsurface investigation along the route of the
hs2 railWay ProJeCt
The ‘MAboUMine’ Mining companywas preparing an industrial projectto open a niobium polymetallic minenear to lambaréné, in gabon’sMabounié valley.
Soil Engineering Geoservices Ltd contractedRobertson Geo to undertake the wireline loggingto measure the Natural Gamma Radioactivity ofthe subsurface down to 50m.
The site was located in an equatorial rain forestand very difficult to access. We also had toovercome the bending effect of the sun scorched50mm diameter downhole plastic boreholeliners. We attempted to use a standard probe of2.2m length and 42mm diameter but due to theextreme heat the liners had been exposed to,they had bent and were curling in the boreholemaking hitting target depth with a probe of thissize very difficult.
Remarkably, the development andmanufacturing departments of Robertson Geowere able to fast track the development andproduction of a small 0.78m length and 27mmdiameter Gamma Probe within a matter of daysto provide the solution to this and enable theacquisition of full data coverage to meet theClient requirement.
Aaron JonesSenior Logging Engineer
This phAse ReqUiRed the logging of 55m deep boreholes for the proposed colne valley Tunnel and viaduct section nearchalfont st peters, south-east berkshire UK.
probes deployed were 3-Arm caliper, formation density, ps logger and high Resolution optical Televiewer (hi-opTv).The data acquired characterised the subsurface properties forsoil structure, formation, rock strength and the presence ofany fractures or faults.
Thumbs up for problem solving in
GaBon
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“ CaliBration is one of themost important aspects of usinggeophysical equipment but alsoone of the most easily ignored.a proper calibration routine isvital to maintain the higheststandards of data quality.
a good example of theimportance of calibration isseen in gamma radiationdensity logs. With time thestrength of the radioactivesource gradually decreases(2.3% per year for caesium 137)and the efficiency of the sodiumiodide detector may decrease.
the log shows the result of this:over the course of three yearsthe raw count rate experiencedby the probe drops noticeably.Calibration allows fieldengineers to maintain readingprecision by resetting the clock,achieving high quality resultsover extended periods.
robertson Geo providescalibration equipment andsupport for all of its probes,helping clients achieve optimalresults for all future operationalneeds. ”
Timothy HamflettTest Engineer
Robertson Geois the only
ISO CERTIFIEDlogging services
provider and the onlycompany whichcomprehensivelyCALIBRATES all of itslogging systems
The consTRUcTion of nuclear power engineering civilworks has started in Xiapu county, fujian province. it is thefirst nuclear power project started in china since 2017. robertson Geo customer, Changjiang survey technology institute wascommissioned by the project department to drill 15 boreholes each with adepth of 200 to 300 meters and an outer diameter of 95mm. the collecteddata will be used for fracture identification and slope stability analysis.
over a five day period, the data logging of the 15 boreholes was completedusing robertson Geo high resolution acoustic televiewer (hrat), electriclog and Full Wave triple sonic probes deployed by a 1000m capacity winch.
ChinaFujian Nuclear
Power Plant
7www.robertson-geo.com
introducing Michael Jones“My name is Michael Jones and i am the newestaddition to the software development team.
i’m from north Wales and thrilled to be backand working with Robertson geo.
i have a background in earth sciences havingcompleted an Msci degree in geology andgeophysics from imperial college london.
When i graduated i entered the miningindustry completing an internship as agraduate geologist on a mine site in Utah,UsA and gained some valuable experience,but then decided to follow a different pathand was employed as a consultant in ahydrology and flood risk consultancy. Thisrole was very enjoyable and multifacetedinvolving field work across the UK,
hydraulic modelling, scientific research and computerprogramming among other things. As the role progressed it became clear that
computer programming was the area which i found most rewarding and stimulating and decidedthat it was something i wanted to do full time and i joined Robertson geo.
i have now been here for over six months (where does the time go?), already i’m fully absorbed inRobertson’s most recent development project. With my earth science background the role feels likea perfect fit for me. i look forward to combining my experience as a geologist and a softwaredeveloper with the success of current and future projects.”
Michael Jones,
Welcome to Robert
son Geo
Robertson Geo Service Teams decided to place their“ready to go anywhere” reputation to the ultimate testby facing the world renowned Tough Mudderendurance event in the grounds of CholmondeleyCastle, Cheshire UK.
The challenge of mud, cold water, teamwork andendurance was embraced with a positive, familiarattitude as each logging job usually involves at leastone of these conditions. The ten-mile-long courseconsisted of a multitude of obstacles ranging from
crawling through muddy trenches, wading throughrivers and climbing over high vertical walls.
An obvious ‘favourite’ being the electric shock therapy,where a mad dash from one end to another throughdangling electric wires was viewed more as an ‘everyman for themselves’ obstacle, rather than the ‘no onegets left behind’ mentality the team used throughoutthe day. Many of the obstacles were impassablewithout teamwork and the event was a great teambuilding exercise.
The service team are all “Tough Mudders”
See you soon!See you soon!Already this year we’ve exhibited atexhibitions and conferences acrosseurope, the Americas, the Middle eastand Australasia.
A geophysicAl And camerasurvey, down to 40m, of two water producing wells has beencompleted for decantae MineralWater in the snowdonia foothills at Trofarth, north Wales.the acquired data was used todetermine the extent, nature andcondition of the water well casing with aview to implementing a plan to increaseflow rates whilst maintaining the highestwater quality. the geologic target andproducing zone was a silurianmudstone at 40m subsurface. the wellsite had one borehole in hilly terrain onlyaccessible with a 4WD vehicle.
the logging of the wells was completedin two visits of one day each. Probesdeployed included Downhole Camera,3-arm Caliper/natural Gamma, electriclog, temperature/Conductivity andCement Bond log.
Following initial set up, the DownholeCamera was run into the borehole and acomprehensive inspection of theborehole and casing was performed inreal-time with the results saved for laterinspection. a temperature/Conductivity
log was then made which providedinformation on the inflow depths. the 3-arm Caliper provided quantitativeinformation on the borehole conditionand the natural Gamma and electriclog helped define the local lithology.Finally, a Cement Bond log was run toprovide additional information on thecasing integrity.
the logging was completed in a timelymanner minimising any disruption to thewater production. Probes were deployedwith 100% reliability, and providedinvaluable information for futuredevelopment. Following loggingoperations, the operator replaced casingfrom the wells as necessary and the wellswere brought back into production.
