New Developments in Underground Mine Surveying

New Developments in Underground Survey| 2010 | Page 1 www.dmt.de

New Developments in Underground

Mine Surveying

by

Norbert Benecke, Volker Schultheiss & Martin Weber

DMT GmbH & Co. KG, Essen / Germany


1. Requirements to be achieved by mine surveyors

Fulfilment of increasing legal and operational requirements for the whole live cycle of a mine, in particular: survey and mapping of the underground structure of mines

monitoring of the impact of underground mining within the mine and at the surface

Fulfilment of these requirements has do be done: with high quality

as fast as possible

safe and environmentally friendly

as economically as possible

Therefore the following qualifications are urgently needed: specialised knowledge and experience of responsible mine surveyors and their staff

advanced survey systems (hardware and software)


No GPS available

Necessity of transferring of coordinates and orientation from surface to

underground (mostly through vertical shafts)

Specific dimensions of survey objects (in particular long tubes with small diameter)

Specific environmental conditions (e.g. temperature, air circulation, dust, water,

possibly explosive gases, light and sight)

Specific requirements on results (e.g. obligations by mining authorities, short-term

availability, time series, 3D-as-built-documentation)

2. Characteristics of underground survey


Use of standard survey devices and data evaluation tools, if applicable

Use of old fashioned (mechanical) instruments in particular in underground coal

mines (explosive atmospheres), developing countries and countries/companies

with a low status of mine surveying

Status of mine surveyors varies massively from country to country (from essential

part of the mine management team to dispensable data collectors)

Some individual developments (= in some mining companies or some countries) of

specific instruments (e.g. explosion-proof electro-optical distance measurement)

Some individual developments of specific data evaluation tools (e.g. adaptation of

tunnelling survey tools to mining tasks)

3. State-of-the-art in underground survey


Orientation (gyroscope)

Shaft survey (inertial measurement system)

As-built documentation and convergence monitoring (laser scanning)

(under progress) combination of laser scanning and inertial measurement

systems for as-built documentation of shafts

4. Overview about latest developments (by DMT)


5. Latest Developments Gyroscope

Requirements on accuracy of tunnel/roadway position are depending on:

Used tunnelling method (e.g. TBM)

Planned use of the tunnel in operation (e.g. high speed railway tunnel / underground roadway)

Examples for challenging requirements in accuracy:

Predefined position of demounting constructions for the TBM (5 cm)

Required alignment accuracy of 10 cm at each tunnel position for high speed railway tunnels

Required accuracy of 20 cm for breakthrough point of two underground roadways (after long distance measurements on surface, through shafts and underground)


Errors in navigation have direct consequences to all following tunnel or mining

processes and threaten the economical success of the project

Advanced guidance systems are highly developed and are enabling the machine

drivers to drive within the given tunnel direction with high precision

But how precise is the correct tunnel direction set in advance? Possible errors by:

Refraction Dust Convergence Plumbing through shafts

Additional measurements with advanced instruments are strongly recommended

Especially measurements with a high precision gyroscope will improve the

accuracy of the survey considerably


Guidance System

Source: VMT GmbH

Tunnel survey System



DMT has almost 60 years of experience in developing, crafting and applying

gyroscopic measuring instruments

GYROMAT3000 is the most accurate gyroscope in the world

Measuring accuracy: 1 mgon =>10 mm/km

Neutral, rapidly rotating gyroscope suspended inside the instrument

Axis oscillating around geographic north as a result of the interaction of the gyro

rotation, gravitation pull and Earth’s rotation

Only 10 minutes measuring time for measurement with the highest accuracy

MW 2002: explosion-proofed version of GYROMAT (measuring accuracy of 2 mgon)


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5. Latest Developments Inertial Shaft Survey (ISSM)

DMT’s Inertial Measurement Unit (IMU): continuous shaft measuring system

High resolution shaft surveys in a vertical direction with no limitation in depth

Very accurate position measurements of the cage to the plump line

Horizontal (X, Y) ±50 mm/1000 m Vertical (Z, depth) ±100 mm/1000 m

Additional guide information in high resolution

Kinematic and geometric shaft properties in relation to depth and time

Minimum of shaft standby (10 times faster than traditional techniques)

Simple mounting of systems devices in or on cages, lifts etc.

Automatic mode, no persons on cage during surveys

Available as explosion-proofed system


5. Latest Developments Inertial Shaft Survey – Example from practice in Australia

Assembly unit screwed onto two mounting brackets, secured on the pair of rails in

the hoist cage

Adjustment of mounting for different track widths as well as different rail

thicknesses

All data recorded are saved on a PC card fitted inside the main assembly

External terminal with optical infrared interface is connected for data transmission

Measurements after initialisation are performed automatically

At first accurate measurement of inclination angle (vertical direction) and

orientation to north (horizontal direction) for determining the start and end

orientation of ISSM


Subsequently the hoist cage is accelerated to the ideal speed of between 4 and 8

m/s, and then the cage is again brought to a standstill and left at rest for 60

seconds

Periods of rest are necessary for carrying out the zero velocity update (ZUPT)

By applying this method the sensor drift that inevitably occurs during each period

of movement is mathematically minimised

The cage is run up the entire length of the shaft in a continuous succession of

periods of movement and periods of rest until the top of the shaft is reached

Finally orientation measurements are made in which the orientation to north and

the inclination angle are again determined

5. Latest DevelopmentsInertial Shaft Survey – Example from practice in Australia


5. Latest Developments3D-Laserscanning

Automotive engineering

Architecture

Archaeology

Monument protection

Forensics

Industrial plants

Mining

Tunnelling

...


As built documentation

Bottle neck analysis

Basis for accounting of construction activities

Monitoring of deformation and convergence (multiple survey campaigns)

Conservation of evidence, e.g. damages or discrepancies

Basis for reconstruction work, maintenance and repair

Profile measurement

Volume calculation, e.g. excavation, concrete thickness, dumping

Geological documentation and analysis

Navigation of machines, e.g. road headers, drilling machines

5. Latest Developments 3D-Laserscanning applications for mining


5. Latest Developments 3D-Laserscanning: IMAGER 5006EX

Usage of commercial 3D laser scanners in hard

coal underground mines is not permitted due to

the potentially explosive atmosphere

Exception from Mining Authority has been given

for some system tests

Development of an explosion proof laser

scanner was required…

… and realized

on basis of commercial laser scanner ZF

IMAGER5006

developed by DMT in cooperation with

Zoller+Fröhlich

Supported by German Coal Mining Industry (RAG

Deutsche Steinkohle AG)


5. Latest Developments

3D-Laserscanning: IMAGER 5006EX

Certified by ATEX (Group I Mining and

Group IIb Other Industries)

IECEx Certification (required for Australia)

is under progress and will be available soon

Compressure resistance

Battery pack can be changed in explosive

environment

Full functionality of ZF IMAGER 5006

portable weight (approx. 30 kg)

Instrument available for purchase or for

services by DMT



3D-Laserscanning: Dynamic shaft measurements

Combination of IMU and explosion-proofed laser

scanner

Mounting of IMU and 2 IMAGER 5006EX on

the hoist cage

1st measurement phase: optimized for IMU (4

to 8 m/s plus standstills) with simultaneous

pre-scan

2nd measurement phase: optimized for laser

scanners (profiler-mode continuously 1 m/s)

with simultaneous IMU support

Measurement duration: approx. 2 shifts for

1000m shaft




Example: Point cloud from laser scanning




Examples: Mounting / Details of point cloud / Deformations (unwrapping)




Examples: Reclamation of an abandoned mine shaft




Examples: Reclamation of an abandoned mine shaft

cross section deformation (unwrapping)


6. Conclusions and Outlook

Legal and operational requirements concerning health, safety and environment on

underground mine surveying are high, both technically and economically

State-of-the-art in underground mine surveying is not/only partly adequate to the

increasing requirements of the mining industry

DMT is international market leader for bridging this gap by

Developing of advanced survey systems

Providing services with these advanced survey systems by experienced

engineers

GYROMAT3000 Shaft IMU IMAGER5006EX IMU/IMAGER5006EX


7. Acknowledgement

Many thanks for your attention !

For more information please contact:

DMT GmbH & Co. KG

Exploration & Geosurvey

Contact: Martin Weber

Am Technologiepark 1

45307 Essen, Germany

Phone: +49 201 172 1675

Fax: +49 201 172 1971

E-mail: [email protected]

Internet: www.dmt.de

mailto:[email protected]

Documents

New Developments in Underground Mine Surveying