mine surveying: the transition from surface to …geomatics indaba proceedings 2015 – stream 2 55...

Geomatics Indaba Proceedings 2015 – Stream 2

55

Mine surveying: The transition from surface to underground

by Colin Bennett, De Beers Consolidated Mines and Michael Livingstone-Blevins, Anglo American Abstract

This general technical paper will provide details of oversight and advisory support of a large underground mine project. It is deemed a necessity to capture and table the processes and learnings of the project thus far. Despite rapid leaps in surveying and measurement technology, the fundamental principles of surveying are still applied in establishing the survey network for underground survey control.

The project entails establishing an underground mine beneath a large operating open pit. Two vertical shafts approximately 1040 m deep, a decline, two return air passes and extensive underground tunnels and infrastructure for mass-mining. First underground production is planned for 2021.

The need to include the survey discipline from the outset of the project has risen as key to the successful delivery of a quality project. Survey errors and delays can have significant safety, schedule and cost impacts. Survey should always be considered in the “planning and design” phases. This will be dealt with in detail as the mine surveying for the project unfolds.

Early recruitment is certainly acknowledged by all disciplines as critical to the project, enabling the timeous establishment of technical systems and processes. However, surveyors with the skills and experience needed for a project of this nature have proved to be extremely scarce. The open pit survey environment is very different to the shaft sinking environment and the skills, thus compounding the scarcity.

The secure survey control network for the open pit becomes redundant for the underground operations once new beacons are established for the project. The survey control needed for the shafts and associated construction must be well planned and established much earlier than most planners anticipate.

The planning and execution of this control network is also more complex than generally appreciated. The transition to a precise engineering survey system must be dealt with as the “new” control network is completed.

The role of the surveyor on a project such as is described above, is one of accurate “setting out” of the plan over many months and years. This entails establishment of the mine design in physical space and measuring compliance with design and schedule. Measuring and reporting all quantities for the “bills of quantities” is sometimes an afterthought, despite being an essential contract management function.

Based on the schedule, and production planning and profiles, the survey section must be staffed with appropriately skilled people, and have available software and hardware to cater for the different survey functions needed in the shaft and development phases.

This paper and presentation will outline the learnings and risk mitigation over a period of three years to-date. The intent is to compile a guideline to reference for future projects of this nature, rather than relying on the memories of a scarce and shrinking skills pool.

Keywords

mine survey, beacon, VUP – Venetia Underground Project, GeoMoS, MHSA – Mine Health and Safety Act, DMR – Department of Mineral Resources, NCSS, Lo (Cape), CADD, COGO, GPS


56

Introduction

The significance of the topic of this general paper is to document the process of transforming a mine from a surface operation to an underground operation from a mine surveying perspective. The unique surveying skills required for such an undertaking are rarely transferred and skill sets are lost to an organisation.

The structure of this paper reflects the journey starting at “pre-feasibility”, traversing to the current execution of the project, tabling the survey actions, findings and finally recommendations.

The feasibility report required substantial reference to the origin of survey and the current status of the original Venetia Mine survey control network. The origin of the mine survey control network and its initial establishment were retrieved from the Anglo American survey archives.

The secure documented history of the original survey network had a significant impact on the transition of the survey control to underground. The subsequent technology improvements were recorded and GPS was used to redefine the final coordinates of the open pit survey network.

The Venetia Mine project has a twin shaft system, together with a decline, followed by access development to two kimberlite pipes. These pipes, K1 and K2 have been mined from the open pit since 1992.

The current technology’s effect on the accuracies and methodology for going underground will be tested as the project progresses.

De Beers Consolidated Mines (DBCM) last sank a shaft in the early 1980s at Finsch Mine. The survey intellectual capital, with respect to sinking and equipping shafts, has been lost across the discipline due to attrition.

Venetia Mine is south of the Limpopo river 87 km west of Musina.

Fig. 1: Venetia Mine location.


57

The 3D graphic in Fig. 2 shows the shafts and decline on the left hand side, access development from the shafts to the two pipes. Development in and around the pipes are shown using centre lines only to emphasise the amount of development to be done. The rolled up figures show that 68 km of development must be surveyed. This excludes the shafts.

Fig. 2: Centre line 3D graphic of development.

The shaft, decline, access and kimberlite development metres are tabled below. The shafts will sink to approximately 1040 m below surface.

Start Finish 2014 2015 2016 2017 2018 2019 2020 2021 2022 TOTAL

DECLINE 04‐Mar‐14 17‐Jul‐17 700 1 925 1 404 481 4 511

PRODUCTION SHAFT 20‐Oct‐14 14‐May‐18 50 420 443 93 64 1 070

DECLINE RAMP 500 TO 900 04‐Jul‐17 11‐Feb‐21 709 1 751 2 053 140 55 4 708

SERVICE SHAFT 16‐Feb‐15 29‐Aug‐19 250 483 244 39 49 1 065

COMMON ACCESS 10‐Apr‐16 03‐Jul‐20 542 919 2 737 966 756 5 920

MAINTENANCE FACILITIES 12‐Feb‐18 01‐Jun‐21 599 617 599 55 1 870

COMMON WATER HANDLING 25‐Jul‐18 29‐May‐21 225 1 095 1 249 431 2 999

COMMON VENTILATION 04‐Mar‐17 12‐May‐21 1 195 652 186 1 577 465 4 075

COMMON GROUND HANDLING 10‐Jun‐17 21‐Sep‐20 403 434 1 088 2 014 3 940

K01 MINING METHOD 07‐Aug‐18 13‐Aug‐22 983 3 324 8 577 8 321 2 085 23 290

K02 MINING METHOD 03‐Sep‐18 03‐Mar‐22 317 1 729 1 459 11 117 533 15 155

Total 04‐Mar‐14 13‐Aug‐22 750 2 595 2 872 4 044 7 802 11 106 16 372 20 443 2 618 68 601

Table 1: Shaft, decline and access development metres.

The origin of the survey network control.

The review of original “trigonometric beacon” survey for coordinates

The Anglo American feasibility requirements for survey resulted in the compiling of seven documents, detailing the readiness of the survey section to move forward on the project. The reports included:

Approved detail mapping database

Verified spatial data and documentation

Accurate and precise geographical network

Final survey control network with high internal precision

Calibration report – downhole borehole gyro’s

Database of verified spatial data – borehole collars

Database of verified spatial data – geological records


58

The detail in these reports entailed a substantial amount of research, validation and review, which in turn prompted a significant amount of survey work. Anglo American standards and guidelines for survey were used to measure compliance to the higher order survey required for the project. Supporting these standards, De Beers Survey “codification” catered for on-mine procedures. This chapter focusses on the critical path taken during that research.

The need to ensure that the target geological body, as well as the sinking project, all remained on the same spatial database was paramount.

The Anglo American Group Survey department established the original survey network. This network added substantial value to the survey component of the project, in that the origin of survey on mine was easily found and of an engineering survey accuracy.

Since establishment of the network, GPS has enabled similar high level accuracy control surveys that are not dependent on line-of-sight. GPS has now been used to verify original control and link this to the extended VUP control network. The journey from the origin through the GPS (WGS 84) conversion to the documented network coordinates as tabled on the DMR plans, needed to be located, studied and understood.

Fig. 3 illustrates the origin and trigonometric beacons used for the network at Venetia Mine.

Fig. 3: Original survey at Venetia Mine.

Name of Mine: Venetia Mine Survey Control System Coordinate System: Lo 29 (Cape) Projection: Gauss Conform Ellipsoid: Clarke 1880(Modified) Scale Factor on central meridian:

1.000 000

Zone width: 2° (1° either side of each central meridian) Horizontal Datum: Cape Datum Height Datum: Mean Sea Level (transferred from Trigonometrical Beacons) Unit of measure: International Metre


59

The review of the Venetia Mine survey network was completed and the feasibility study reports submitted. However, the network had not been “check surveyed” by independent high order survey since the conversion from Lo (Cape) to Lo (Hartebeesthoek 94). It was decided to commission an independent external survey to confirm the current network and elevations on Venetia Mine.

The planned high order independent external network survey check

The resurvey of the original network for co-ordinate comparisons

The network, comprising beacons BCN 1 to BCN 6 on the property, remained the focus for the resurvey. Some beacons had line of sight restrictions and access to others had become restricted due to security requirements. Secondary, or Class B beacons, did not form part of the resurvey but will be considered for resurvey and inclusion at a later date.

The specifications for the resurvey were tabled and confirmed by Anglo survey management in its oversight and assurance role. GPS post processing was used when surveying the beacons. At least one hour of data collection at each beacon was required, taking into account the satellite constellations, PDOP and other technical factors. A minimum of six satellites was specified.

The required specifications are:

Type of total station, accuracy and OEM specifications

Type of level, accuracy and OEM specifications

Type of GPS, accuracy and OEM specifications

Calibration certificates

Baseline check on sight

Barometer specifications and checks

Temperature checks for wet and dry bulb thermometer

Methodology and sequence of survey

Distance and angular measurements at all stations

The network was adjusted by the “least squares” method.

Where the required accuracy was not obtained, beacons BCN 1 – 6 were re-observed. EDM observations between inter-visible beacons were necessary for ratification of the GPS survey. The external vendor undertaking the survey used approved software for the GPS network adjustment and loop closures. All the survey instruments used were also checked and approved.

Fig. 3: The resurvey of the original elevations through precise leveling.


60

An “engineering project” calls for an accuracy of 2 mm or less in Y, X, Z. Precise leveling is the most accurate method of determining elevation. Much of the construction work on the project terrace and shafts has a high dependency on the Z component. The elevations on the beacon are used for general surveying in the tertiary area of surface survey. The additional stud built into the beacon at its base is used as precise elevation for Class A and “engineering” surveys.

Fig. 4: New project "tower" beacon under construction.

The bench mark of the mine

The resurvey of the mine and project bench mark beacon, BCN 1, both for co-ordinates and elevation, confirmed that nearby excavation resulted in movement of the beacon. The request was to re-run the adjustment of the network leaving BCN 1 as a free station. This process confirmed the movement and the adjustment was re-run excluding BCN 1.

This was a significant decision, as primary survey and elevations had been established from BCN 1. The beacon was demolished and the mine network beacons that were inter-visible with the shaft beacons were included in the planned shaft network. All coordinates, however, remained directly referenced to the mine and project benchmark.

COORDINATES WITH BCN1 AND BCN2 FIXEDSystem : LO 29 Ellipsoid:Clark1880Geoid:SAGeoid2010

GPS RESULTSCALCULATED POINTS

NAME EASTHING NORTHING HEIGHTBCN5 -32619.397 2483252.967 717.908BCN2 -32177.455 2482941.183 699.707BCN1 -32414.9402 2482569.507 724.7764BCN10 -32272.266 2482545.856 723.2028BCN7 -32535.9501 2482625.972 718.266BCN8 -32547.8911 2482264.434 714.8986BCN9 -32286.0293 2482170.757 720.4392

A survey network for the decline development portal and the terrace area for the shafts

Survey extensions to the decline portal

The construction in and around the decline portal preceded the re-survey of the beacon, due to delays in the terrace construction. After the initial centre point was established and the subsequent blasts taken, a new survey was brought in from the original Venetia Mine “open pit” network. This network included BCN 1 which was later compromised due to nearby blasting and excavation.


61

Fig. 5: BCN 1to be demolished – note adjacent excavation.

The development in the decline remained on schedule and ahead of the terrace construction. Beacon construction became a critical issue. In the interim, the new network would be completed and the decline survey system checked for x, y and z variance.

A design change led the decline into an early change in direction and resulted in a sub-optimal baseline for underground traversing. A direction check by gyro became critical, as was the first check survey from the new survey network.

The higher order external gyro survey using a Gyromat 3000 was managed by Johan Swanepoel, survey manager at Zibulo Colliery, Anglo American Inyosi Coal. The on-site team comprised Mohamed Karrim and Jonathan Tollemache.

The surface calibration was done on two bases: BCN 5 to BCN6 and BCN 5 to BCN 1 (pre-movement). The mean “e-value” result, shown below, is used in the determination of the underground bearings.

Table 2: Surface calibration.

The underground gyro survey was conducted at pegs U0010 and U0008. The mean results were then used to compare to actual alignment (bearing) versus design. The three second of arc difference between the original survey taken underground from the surface network, versus the gyro bearing is excellent.


62

Table 3: Underground gyro vs traverse comparison.

The results and comparisons can be shown on the statutory plans as required by the DMR. As reassuring as this may be, the number of development working places and changes of direction (>100) will necessitate additional gyro base check surveys to continually confirm direction. A dedicated gyro has been ordered.

The terrace area

Planned beacons for the terrace areas took into account planned infrastructure with emphasis on line of sight. These planned positions became obsolete as the project schedule changed. Alternative positions for the beacons were introduced. Due to the on-site construction causing damage and movement to the beacons, it was not a viable option to construct beacons on the terraces as planned. It was decided to construct beacons outside of the terrace area, but still practical for future use.

Fig. 6: New beacon on terrace (within scaffolding).

Survey extensions to the shafts

The second phase of extension to the network was to extend the survey system into the shaft area to cater for the winder houses and headgears.

The shaft centre points and subsequent pre-sink work was still based on the original “open pit” network and needed to be incorporated into the new shaft network. The check survey to each shaft was a priority and is dealt with in the following chapters.


63

Results from the independent survey check

The external resurvey was undertaken by AAM. Not all the methods and results can be viewed in this chapter, but it is important to note that the resurvey showed movement in the primary beacon BCN 1 of the original Venetia Mine survey network. An extract from the report shows movement of 12 mm and 8 mm for BCN 1 as well as 15 mm and 1 mm for BCN 6. HELMERT TRANSFORMATION BEACONS EXCLUDED FROM TRANSFORMATION NAME Y X dY dX DESCR BCN1 -32414.9410 2482569.5020 (test) BCN1 -32414.9330 2482569.5030(BEACON COORDS FROM VENETIA MINE) BCN1 -32414.9451 2482569.4950 0.0121 0.0080 BCN6 -32578.6782 2482931.6260 (test) BCN6 -32578.6660 2482931.6240(BEACON COORDS FROM VENETIA MINE) BCN6 -32578.6811 2482931.6222 0.0151 0.0018

The co-ordinate results of the resurvey, the results from the precise leveling and resurvey beacon BCN 1 proved that the network was compromised and that the bench mark should be excluded and the network adjusted accordingly. The leveling results, shown in Table 4, substantiate the concerns for beacons BCN 1, 3 and 6. The BCN 4 beacon was in a security area and could not be leveled.

Table 4: Leveling comparisons.

The continuous philosophy of “check surveying” by VUP surveyors on all contract work performed, confirmed that the required higher order engineering surveying accuracies were maintained. Despite that fact that a transition from the original Venetia Mine network to the new “shaft network” was in continuous progress, accuracy and integrity was retained.

The primary beacons, listed in Table 4, are supplemented by secondary beacons throughout the mine, which cater for general surveying. The secondary beacons that are situated around the existing pit play a significant role in the daily surveys of the pit. The pit slope monitoring stations that house the GeoMoS movement monitoring systems are checked from the original network on an annual basis. All these processes have been reassessed and the new network will now drive the pit surveys. All of the abovementioned survey control are fit-for-purpose and part of a single homogenous system.

Transformation from Lo to engineering survey system

The expertise of the Anglo survey team was secured to train the surveyors and to introduce the transformation application on all survey systems at Venetia Mine.

There are substantial differences of opinion between the contributing departments on a project as to which survey system is appropriate.

Engineering design is typically represented in a 2D environment, with plan, side section and front section. It is common practice to have hard copy plans as the deliverable to the site.


64

Prior to mine design, geological information would need to be “geospatially assured” and referenced to the project coordinate system.

Land surveyors would prepare plans in relation to roads, rail and land ownership in the appropriate formats.

Mining projects would only bring mine surveyors onto a project site late in the construction phase.

The mine surveyors are obligated by law, namely the MHSA, to compile plans on the National Control Survey System (NCSS) or, where exemption has been obtained, on a local system. The NCSS introduces curvature and projection corrections, as well as reduction to mean sea level for elevations, which are unsuited to engineering surveying and construction.

Venetia Mine has a well-established survey system on Lo (Cape) with transformation to Lo (Hartebeesthoek 94) shown on each plan. In order to accommodate the abovementioned corrections, transformation to a fixed Engineering survey system was a necessity. The engineering system is suitable for the construction, sinking and equipping of the project but the planned Decline, already several hundred metres developed, required that the Venetia open pit and infrastructure be fixed relative to the decline. Additionally, several geological boreholes were drilled in and around the shaft area which are considered void hazards which must be shown on all underground development plans.

It was decided to keep the shaft and associated construction on the engineering system and the decline development on the local system, reduced to sea level.

Using the preliminary BCN1 and BCN5 derived coordinate transformation parameters, the remaining Venetia mine beacons are transformed from Lo29 to engineering.

This was regarded as a training and development exercise for the VUP survey team. The resurvey and establishment of the shaft network would require the same exercise and transformation for the project area.

The higher order survey of the shaft network

The newly installed shaft beacons as well as identified original network beacons were included in the shaft network control.

Several planned versions of the shaft terrace area beacons were adjusted to ensure or enhance line-of-sight. The example in Fig. 7 illustrates the early attempts at placing external and internal beacons on the terrace for the shaft network. The external beacons were planned to be built before the terrace had been completed, while the internal beacons on the terrace would later assist with the intricate surveying of headgears and winders. Not all the beacons were constructed in the selected areas and, as more construction was completed, the placing of the shaft beacons became more challenging.


65

Fig. 7: Proposed beacon positions on the terrace.

Surveyors have the expertise to plan, design and erect beacons to the correct specifications. In this case, however, the construction was assigned to civil engineering contractors on site. Procurement and document control was reflected in the “green stamp” approved design submitted to contractors for tender and construction.

Fig. 8: Detailed design for beacons on terrace.


66

As with the resurvey of the original mine beacon network, the new shaft network was surveyed to high order based on specifications laid down by Venetia Mine survey section.

Orthometric heights for all beacons were determined from precise levelling of beacons. Various GPS network adjustments, based on different combinations of fixed points were calculated, to assess the integrity of the original mine network. This process identified minor movement in some original network beacons (and major movement in BCN 1 as previously mentioned).

The final network would include the two most stable beacons from the original network, namely BCN 2 and 5. Although the final table included BCN 1, the results showed further movement in both x, y and z. The decision to destroy the “bench mark” was taken.

Finally, overall accuracy of the GPS established network was checked using total station angular and distance measurements, to confirm compliance with accuracy specifications.

Point Id Point Class Easthing Northing Ellip.Hgt. Ortho.Hgt. Sd. Easthing Sd.Northing Sd.Height

BCN5 Control ‐32619.397 2483252.967 715.2321 717.908 0.0001 0.0002 0.0002

BCN1 Adjusted ‐32414.9403 2482569.508 722.0828 724.7767 0.0003 0.0003 0.0007

BCN10 Adjusted ‐32272.2661 2482545.857 720.508 723.2032 0.0004 0.0004 0.0009

BCN2 Adjusted ‐32177.455 2482941.185 697.0215 699.7073 0.0003 0.0003 0.0007

BCN7 Adjusted ‐32535.9502 2482625.973 715.5744 718.2664 0.0004 0.0004 0.0009

BCN8 Adjusted ‐32547.8913 2482264.436 712.1981 714.899 0.0004 0.0004 0.001

BCN9 Adjusted ‐32286.0295 2482170.758 717.7351 720.4396 0.0004 0.0004 0.0009

A full report included: Calculated points report network adjustment

Coordinate comparison report

Final coordinate list

Final VUP coordinate list

Leveling reduction from BCN 2 and BCN 5 to the new beacons and their studs

Leveling comparison report

Loops and misclosure report

Network adjustment report

Venetia Mine Survey report

Final coordinate listSistem : LO 29 Ellipsoid:Clark1880Geoid:SAGeoid2010

NAME EASTHNG NORTHING HEIGHT TOP OF BEACON STUD HEIGHTBCN1 -32414.940 2482569.508 724.777 720.8547BCN2 -32177.455 2482941.183 699.707 695.8450BCN3 -31992.299 2483219.249 695.264 691.373BCN4 -32239.557 2483317.256 707.913 no levelBCN5 -32619.397 2483252.967 717.908 714.030BCN6 -32578.678 2482931.626 710.529 705.045BCN7 -32535.950 2482625.973 718.266 718.2522BCN8 -32547.891 2482264.436 714.899 710.6350BCN9 -32286.030 2482170.758 720.440 715.8793BCN10 -32272.266 2482545.857 723.203 718.5056

It must be noted that at the time of completion of the new extended survey network, the two vertical shafts had already reached a depth of 60 m, while the decline had advanced about 700 m. To address the risk of significant error in surveys due to the schedule change and construction constraints, regular check surveys were critical to confirm compliance with design. The gyro base in the decline supported the numerous check surveys taken


67

down by the contract surveyors and confirmed by the check surveys done by the company surveyors. The importance of survey assurance cannot be over-emphasised.

The shaft steady brackets and associated plumb wires were positioned as planned.

Personnel, hardware and software

The mine surveyor is acknowledged in numerous market surveys as a scarce and critical skill. Furthermore, there is a shortage of senior surveyors with shaft sinking experience.

De Beers last sank a shaft in the 1980s and the mine surveyors of that era are no longer employed by De Beers resulting in the loss of intellectual capital. There are very few of these people in industry. Fortunately, many surveyors want to part of a project of such challenge and complexity. Shaft sinking and equipping is rare, but a transition from open pit to underground is a once in a lifetime opportunity.

Precision systems, which incorporate scanning and photographic capabilities, have replaced the mechanical theodolites that were used on the station breakaways 30 years ago, and more recently conventional total stations. The surveyor is now required to be CADD competent in a complex 3D environment and must be highly competent in using onboard COGO software on survey instruments to achieve maximum productivity and minimal disruption to sinking and development activities..

Legislated survey accuracy is significantly less accurate than that required for engineering surveying. A blunt but simple limit of error is stated as 2 mm for the control network and 3 mm for all other construction surveys.

The accuracy and final success of the project is the responsibility of the owner’s team surveying section.

To address the abovementioned people, process, technology and standards requirements, experienced surveyors should be included in the in the pre-feasibility and feasibility stages of the project. The early establishment of an engineering coordinate system and engineering survey network would avoid unnecessary debate, confusion and interventions caused by design, survey and procedure discrepancies.

Bills of quantities should be measured or authorised and checked by the owner’s team.

The survey section on a mine is the custodian of quantities and, in several cases, qualities. All bills of quantity which require survey measurement, verification and authorisation should the responsibility of the owner’s team surveyors, i.e. contractors monthly bills of quantity are not acceptable. Initially, the survey function was the responsibility of the contractor(s), thereby compromising this critical control.

The integration of the contract and owner’s team surveyors was initially difficult but necessary. This highlighted the need for standardisation of hardware and software and systems.

The need to have one version of truth also points towards a single source of spatial information required for the construction and development of a new mine. It is therefore logical to have all the surveyors on the same network server, using the same software for standardised output to project clients. One must then examine the capturing of data, not only the management of the spatial data. Furthermore, survey instruments must be capable of complying with the limits of error specified for the project.

The Leica MS50 multi-station has become the instrument of choice, due to its ability to perform all the functions of a high-end total station, as well as point cloud scanning. It contributes significantly to surveying productivity, and dimension control compliance and assurance. Where the external higher order resurveys are conducted, the project specifications are tabled to the companies that conduct the work. As mentioned above, all equipment must be “fit for purpose” and pass on-site calibration checks.

Closing remarks and recommendations

Although there was survey participation in the feasibility study and reports of the project, this was a late inclusion. The closing chapter will draw attention to areas that need further attention. Early reviews and participation in the design of key survey criteria are recommended to establish an optimal survey process throughout the project.

The required network on surface, at specific limits of error, must be transferred via plumb wires down vertical shafts to underground, to extend the spatial control accuracy required for the project.


68

This spatial control is then transferred to “lines and grades” for kilometres to intersect the ore body. Inter-level connections, underground infrastructure establishment and mine operations mobile equipment rely on this spatial accuracy.

The early design of the project is typically engineering design. Mine surveying encompasses the projection corrections as well as reduction to sea level. The transformation to a local engineering survey system is crucial to the project, particularly for prefabricated infrastructure components, 1 m on the ground is equal to 1 m on plan.

This survey system calls for control in the form of robust beacons being available in the right position at the right time.

The most important elements in the vertical shafts are the plumb wires and the steady brackets. Survey must be able to review design of these wires, both in number and access to utilise and extend. The shafts, including all the construction, rely on these wires for geometric control and position. Placement and accuracy of the wires are paramount. The design and positions of the wires must be overlaid on both sinking and equipping plans, as part of a clash detection and mitigation process.

The survey section is responsible for all “bills of quantities” for the project. It should have the correct systems, people and support to deliver all the necessary information to management.

Finally, the high order of survey required needs the experience and skills for project work. Not only is there a requirement for precise engineering survey, the sinking and equipping phases require particular experience, skills and survey knowledge.

Timeous and thorough planning which addresses people, process and technology will ensure minimum survey stoppage time, fast survey turnaround time and effective establishment and monitoring of the mine design in physical space, i.e. the optimal contribution by survey to deliver a quality project. Acknowledgement Appreciation is expressed to De Beers executive leadership for permission to publish this paper and thereby transfer knowledge and experience to the greater surveying community. References [1] HG Thomas: M.Sc, Pr. MS (SA), Coordinate transformation

[2] AAM network survey reports

[3] Anglo American survey archive

[4] De Beers pre-feasibility and feasibility study documents for the Venetia Underground Project

[5] Anglo Inyosi Coal, Zibulo Colliery

Contact Colin Bennett, De Beers Group Services, Tel 011 309-3535, [email protected]

mine surveying: the transition from surface to …geomatics indaba proceedings 2015 – stream 2 55...

Documents