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НОВЫЙ ПОДХОД К БЕЗОПАСНОМУ, БЫСТРОМУ И ТОЧНОМУ МОНИТОРИНГУ ГЛУБОКИХ ШАХТНЫХ СТВОЛОВ
Норберт Бенеке
DMT GmbH & Co. KG, Exploration & Geosurvey Division, Германия Мартин Вебер
DMT GmbH & Co. KG, Германия, Am Technologiepark 1, 45307 Essen, инженер-геодезист, руководитель отдела лазерного сканирования, tel: +49 (0)201 172 1675, fax: +49 (0)201 172 1971, mobile: +49(0) 175 265 3996, email: [email protected]
Большинство высокопроизводительных горных работ, в частности подземные разработки, выполняются в максимальном объеме. Поэтому бесперебойная работа шахтных стволов является успехом проведения горных работ. В связи с постоянной эксплуатацией ствола шахтные установки подвергаются износу. Кроме того, воздействие на ствол и его участки оказывает и околоствольный двор (комплекс подземных горных выработок, пройденных вблизи шахтного ствола). Поэтому для шахт очень важен тщательный мониторинг, что позволит исключить любые повреждения и обеспечит своевременное техническое обслуживание и ремонт задолго до возникновения угрозы безопасности.
В данной статье предлагается новый подход для безопасного, быстрого и высокоточного мониторинга глубоких шахт. Существуют две системы, одна предназначена для стволов с клетевым подъемом или скиповых установок, а другая для стволов без каких-либо установок. Обе системы разработаны в компании DMT, включают в себя лазерный сканнер для профилирования в кинематическом режиме во взаимодействии с инерциальным измерительным блоком и ряд измерительных приборов. Обе системы рекомендуются для работы в потенциально взрывоопасных средах каменноугольных шахт.
Обе системы уже используются в ряде проектов по мониторингу шахтных стволов в Германии. В статье приводятся некоторые результаты. В заключении рассматриваются перспективы использования систем в процессе горных работах в других странах, например, в России.
Ключевые слова: мониторинг шахтного ствола, кинематическое лазерное
сканирование, инерционный измерительный блок, система противовзрывной защиты.
NEW APPROACH FOR SAFE, FAST AND ACCURATE MONITORING OF DEEP MINE SHAFTS
Norbert Benecke
DMT GmbH & Co. KG, Germany, Am Technologiepark 1, 45307 Essen, Chartered Mine Surveyor (Markscheider), Market Manager Mining, tel: +49 (0)201 172 2012, fax: +49 (0)201 172 1971, mobile: +49(0)160 7150874, email: [email protected]
Martin Weber
DMT GmbH & Co. KG, Germany, Am Technologiepark 1, 45307 Essen, Surveying Engineer, Head of Laserscanning Department, tel: +49 (0)201 172 1675, fax: +49 (0)201 172 1971, mobile: +49(0) 175 265 3996, email: [email protected]
Typically high-performance mining operations, in particular underground operations, are producing closely to their capacity limits. Therefore 24 hours operability of the shafts is essential for the success of the mining operation. Due to the permanent use of the shaft the shaft installations
are subject of wear. In addition commonly the shaft safety pillar is mined and this affects the shaft or parts of the shaft. Therefore it is important for mines to monitor the shaft carefully to avoid any damage and to start maintenance and repair before any safety risk can occur.
Within this paper a new approach for safe, fast and highly accurate monitoring of deep mine shafts will be presented. Two systems are available, one for shafts with hoist cage or skip installations and one for shafts without any installations. Both systems have been developed by DMT and both consists of profiling laser scanner in kinematic mode in interaction with inertial measurement unit and some additional measurement devices. Both systems also are developed for use in potentially explosive atmospheres in colliery shafts.
Both systems are already in operation for several shaft monitoring projects in Germany. Some example results will be presented. The paper will be finalized by an outlook to the use of the system in international mining operations, e.g. in Russia.
Key words: Mine shaft monitoring, kinematic laser scanning, inertial measurement unit, explosion-proofed system.
Introduction
Typically high-performance mining operations, in particular underground operations, are producing closely to their capacity limits. Therefore 24 hours operability of the shafts is essential for the success of the mining operation. Due to the permanent use of the shaft the shaft installations are subject of wear. In addition commonly the shaft safety pillar is mined and this affects the shaft or parts of the shaft. Therefore it is important for mines to monitor the shaft carefully to avoid any damage and to start maintenance and repair before any safety risk can occur.
The following type of impact can happen to shafts [BENECKE 2010]:
- in position (inclination, rotation, lateral movements, curves)
- in shape (compression, deformation)
- in function, with following consequences:
- shaft hoisting installations move out of regular position
- hoisting speed of the cages must be reduced
- production losses
- production breakdown
- safety risks, e.g. danger to life or physical condition of workers
Therefore shaft inspection and monitoring is important for any shaft under operation as well as for abandoned shafts for different purposes, like regular inspection on changes and damages, monitoring whilst mining activities are impacting the shaft or as basis for repair work, reconstruction work or shaft closure work. In all cases diverse information will be needed, e.g. detailed documentation and condition of guides, walls and installations, slope, deformation and damages of shaft walls, plumbing of coordinates to deeper mine levels.
Even it is important to acquire this information, the acquisition is difficult due to specific and dangerous conditions for any survey in a mine shaft, e.g. the risk to fall down the deep hole, the particular environment with dust, water, probably extreme temperature and darkness as well as the limitations in space and time window for surveying.
Traditional survey systems for shafts are not fulfilling the requirements on safety, fastness and accuracy:
- Safety: mostly remote operation, no men in dangerous position in the shaft
- Safety for coal mines: system must fulfil safety requirements concerning presence of methane gas
- Fastness: a measurement duration (equivalent to operation down time) less than 1 shift per shaft is requested
- Accuracy: some millimetre in local details, approx. 10 - 20 cm in absolute coordinates
Therefore DMT has developed two new innovative shaft survey systems, for shafts with and without cages which will be presented in this paper.
Cage-Based-Shaft-Survey-System
The main idea for this system is the use of kinematic laser scanning technology, already known from street or rail mapping, but in vertical direction, downwards in deep mining shafts. However, this is not an easy approach; it was really a challenging research and development. In particular, because of the missing availability of GNSS data, the specific environmental conditions in mining shafts (e.g. dust, humidity, dirt, methane gas in coal mines) and the strict safety regulations.
The system layout is as follows (Fig. 1):
- Installation of IMU and two laser scanners IMAGER 5006i on hoisting cage; if requested as ex-proofed version
- Kinematic survey of the shaft with both technologies:
- measurement of absolutes shaft position by IMU
- simultaneous data logging (shaft walls and installations) of both scanners in profiler mode
- Odometer for depth control
- Internal power supply and data storage
- Control unit for synchronisation purposes
The system was developed by DMT and tested on several coal mines of RAG Deutsche Steinkohle AG in Germany. Depending on the client requirement several different results can be evaluated:
- Point cloud visualization in 3D and unwrapping (Fig. 2)
- Deformation analysis
- Cross sections
- CAD modeling of installations (Fig. 3)
- Detailed measurement of position and distances of guide rails (Fig. 4)
- Absolute positioning track
Fig. 2: 3D point cloud
Fig. 3: Cross-section: Point cloud to CAD
Fig. 4: Guide rail measurements
The main features of the system can be concluded as follows:
- Three-dimensional digital object documentation by kinematic laser scanning while cage driving
- Remote and complete 3D-documentation of shaft walls and installations (e.g. Guide rails, pipelines or spreaders) with damages and anomalies
- Absolute positioning and deviation from verticality by inertial measurement technology
- Fast, easy and complete data acquisition independent from lightning or surface conditions
- Safe execution of survey without dangerous work inside the shaft
- Fulfilment of EU (ATEX) regulations, the worldwide highest standard concerning use of electrical devices in explosive areas [EUROPEAN PARLIAMENT 1994]
- Highest reliability and accuracy
- absolute accuracy (for depth of 1,000 m): 10 cm
- relative accuracy of laser scanner measurement: 1mm at 10m distance
- Manifold options for data visualization and analysis (e.g. 3D, Virtual Reality, Video, CAD)
Wireline-Shaft-Survey-System
In particular in Germany a large number of abandoned shafts are already not back-filled for several reasons (e.g. use for water pumping). Also a huge number of very old mine shafts (approximately more than 10,000 with an age of some hundred years) are existing, which become more and more cause for damages to the surface, like sinkholes (Fig. 5).
Fig. 5: Sinkhole caused by an old mine shaft
DMT was asked by clients if there will be an opportunity to do scanning of these old mine shafts, where typically no cage is installed. After some trials testing DMT developed the Wireline-Shaft-Survey-System within the framework of a European Research Project [MISSTER 2012].
The general system layout is presented in Fig. 6a and the main components of the measurement unit are shown in Fig. 6b. These main components are:
- 2D-Laser scanner (,Profiler’)
- Inertial Measurement Unit (IMU)
- Sensor for barrier identification
- Gas sensors (O2 and CH4)
- Power supply
- Data processor and -storage
Eigengewicht Messsystem 200kg
Fig. 6: a) General System Layout and b) Main Components of Wireline-Shaft
Survey-System
Even the system layout is different from the cage-based-system, the results and option for data evaluation and visualization are more or less the same. Fig. 7 illustrates the extremely high quality of the acquired data from a tubbing shaft.
Fig. 7: Detail of point cloud and surface model extracted from data acquired with
wireline-shaft-survey-system
Also the achievable reliability and accuracy of the measurements with the wireline-shaft-survey-system is extremely high:
- absolute accuracy (for depth of 1,000 m): 20 to 30 cm
- relative accuracy of laser scanner measurement: 1cm at 10m distance
Summary and Outlook
Due to requirements of customers from the underground mining industry DMT has undertaken two innovative developments in shaft surveying:
- Cage-based-shaft-survey-system
- Wireline- shaft-survey-system
Both systems have been presented by examples from practice. Both systems are already operational and can deliver extremely reliable and accurate surveying results. Measurements with each of the systems will provide the following benefits to the customer:
- Faster re-availability of the shaft for operational use
- saving of measurement times
- minimizing of down-time
- Enhancement of safety level
- avoiding of dangerous work inside the shaft
- saving of lightning effort
- first opportunity to use laser scanning in explosive areas
- minimizing of required safety measures
- decrease of accident risk for workers
- Enhancement of quality, reliability and rapidity of decisions
- increase of measurement quality and detailedness
- fast availability of results in applicable shape for different themes
- opportunity for evaluation of additional results without additional survey
- Comparison of several survey campaigns
- Saving of time and costs
Both systems are available now for world-wide services as well as for purchase. However, development will go on, e.g. the integration of video cameras and thermal sensors are under preparation.
References
[1] BENECKE, N.; KUCHENBECKER, R. (2010): New Developments in Survey Instruments and Methods for Underground Mining; XIV Congress of the International Society of Mine Surveying (ISM); Sun City (South Africa)
[2] EUROPEAN PARLIAMENT (1994): Directive 94/9/EC of the European Parliament and the Council of 23 March 1994 on the approximation of the laws of the Member States concerning equipment and protective systems intended for use in potentially explosive atmospheres
[3] MISSTER (2012): Mine shafts: improving security and new tools for the evaluation of risks, European RFSC Research project
© N. Benecke, M. Weber, 2013
