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Automation, Mining and the Environment: Where are we Heading?
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Automation, Mining and the Environment: Where are we Heading? TOM P FARRELL Technical and Commercia l Services CRA limited, Me lbourne
Ab stract , The role of automation in the environmental management of the various stages of mining projects is discussed, Remote sensing can be useful in the exploration phase, but tends not to have sufficient resolution for individual operations. Automatic samplers, whether for meteorology, air or water, are widely used, but can have operational problems. The environmental scientist, the electronics engineer and the computer programmer must combine in the future to develop products which are applicable, robust and simple to use . Keywords, Computer software; environment control; mining.
data acquisition;
INTRODUCTION
data reduction and analysis;
predicting the inter-relationships both within them and between them and the external environment. As the geologist s were hampered by the vastness of the Australian continent. so too were the natural sc ientist s, It was only in the early 1950's, for example. that the Northern Au s tralian lands cape was extensively studied. but again the problem of scale meant that very general technique s had to be developed (Christian and Stewart. 1953) . Even today. there are vast ar eas of the continent that have had barely a glance by natural scientists ,
Less than twenty years ago, mineral exploration, and the subsequent development and processing of the discovered ore, were the almost exclus ive realm of the geologist, mining engineer and metallurgist. Other professionals, from accountants t o engineers. provided support for those whose task was seen to be the di scovery and ultimate exploitation of a mineral resource. Indeed. some people may even have r egarded their role as dominant over all others. Subsequently , however . we have seen the upsurge of other professions which vie with those "classical" professions for important roles in the industry, Among these are two that are particularly relevant t o thi s symposium the electronics engineer and the environmental specialist .
The result of thi s is , of course. that when confronted by the need t o report on the natural environment of a prospective minesite. the environmenta l scientist is frequently hampered by the lack of information available about the area .
It is the aim of this paper to examine the often compleme ntary roles of these specia li sts in the different phases of a mining operation. and to examine deficient or problem areas where their spec ialities may be used in the future .
In an attempt to overcome this problem. some have turned to satellite imagery to give at least a s mall scale data s et on which to base larger scale interpretation. One of the mos t s uccessfu l examples of such studies has been the seven volume publication "The environments of South Australia" (Laut and others. 1977). whi ch contains the environmental information that was prepared for a study entitled "A feasibility study for an ecological survey of Australia". Beca use of the enormous area invo lved . extensive use wa s made of Landsat imagery for base mapping. Nevertheless. this is still no substitute for detailed on - the - ground inspection; where it is useful is in enabling an initial asse ssment of the relative importance of a particular l andscape or. less conclusively. vegetation type.
THE EXPLORATION PHASE Not so long ago. people s ear c hing for minerals pi c ked up clues simply by walking over the ground and examining it visually. Rocks stained a particular co l o ur, sudden changes in vegetation. material thrown up by burrowing animals - all these could provide evidence of a mineral depos it , Nowadays. the exploration work often starts with images o f the ground obtained by an orbiting s atellite such as Landsat , With computer te chniques. a researcher can analyse the image to l ook f or changes in structures or base geol ogy which may indicate the prese nt of a depos it.
Despite the large advances over re cent year s in the resolution of satel lit e imagery. and subsequent computer enhancement and numerical analysis . ground truthing is still necessary . This important fact is unfortunately sometimes forgotten in the rush to produce elegantly presented publi c ations. or reports for
Similarly, in the past. scientists studying the natural environment reli ed on cove ring the ground on foot or by vehicle. recording the pres ence or absence of plants and animals and 21
T. 1'. Farrell
clamouring regulatory authorities. Two major problem areas immediately spring to mind; firstly. it can easily be forgotten that satellite imagery is comprised of electronic signals and is not photography in the commonly accepted form. Colours are assigned during processing on the basis of the energy reflected from the earth's surface. and the spectral signature of vegetation can vary greatly depending on the season. water avai'lability. or whether it has recently been subjected to stress. for example burning. Thus differences observed on the image may be artefacts and may not represent actual differences on the ground. The second problem area is the scale of such imagery. and consequently the poor resolution obtained. While the most recent Landsat satellite has a resolution of around 70 metres. this still means that small scale features of interest to the environmental scientist cannot be discerned. Although new satellites are being prepared with much better resolution. in the order of 10 metres. satellite imagery will probably still remain best suited for broad scale repetitive inventory. as described by Foran and Pickup (1984). THE FEASI8ILITY STUDY PHASE As the exploration phase passes into the feasibility study phase. environmental studies become more and more site specific. and begin to concentrate on the actual and perceived impacts of a potential mining or mineral processing operation. Two important factors need to be considered at this stage: what data need to be collected and how best to collect them; and how best to organize the data so obtained in order to minimize impacts while. at the same time. monitoring these impacts. It is also at this stage that an Environment Impact Study is produced. In the early stages of feasibility studies. especially for a deposit in a remote location. personnel are not on - site full time. and therefore data collection needs to De organized on a campaign basis or be automated in some way. For basic physical information. e.g. meteorology. this most likely mean the installation of an automatic data aquisition system. For some time small "package" weather stations. which record a variety of meteorological information on paper charts. have been available in Australia. Such systems have proved in the past to be extremely robust and reliable. with the major problems appearing to lie with the timing mechanism or with pens that become blocked or dry out. The latter problem has been overcome to some extent by the introduction of felt-tip pen cartridges. In some high humidity tropical areas there have been problems with charts tearing after becoming saturated with moisture. In addition. chart changing has been a skill which many technicians have lacked. The greatest difficulty with these systems has been the processing of the often voluminous charts obtained from them. Although chart digitising services are becoming more and more available. these are expensive a~d time consuming. Thus. the "second generation" of recording devices - electronic data loggers has appeared. These. powered by batteries and backed up by solar cells. frequently scan a variety of recording instruments and write raw or processed information onto magnetic tape or. more recently. into electronic data storage
modules. Although potentially more reliable than the mechanical systems. many of those currently in use in Australia have been plagued with problems (see for example John. 1982). The most common fault appears to be the sensitivity of electronic systems to environmental extremes. This unreliability of such equipment. coupled with the comparative state-of-the-art nature of it (e.g. most serial numbers are below 100). has led to its use being abandoned at some remote sites. Nevertheless. if these problems can be overcome. such equipment would appear to be the simplest to install and use. Already. a third generation of these automatic weather stations is becoming available - those that transmit signals in real time through geostationary satellites to ground stations. where they are recorded in computer storage for subsequent processing (Allison and Morrissy. 1983) . Once data have been recorded. it should be a comparatively simple matter to read it off the recording medium into more accessible storage in a micro- or mainframe computer. However. in my experience. this is complicated by the absence of a strict industry standard in communication devices. and the appalling unreadability of most documentation. The concept of "user friendly" has certainly not progressed to this level. Although strictly outside the scope of this paper. the subsequent storage and accession of any such data must be important in environmental programs. Until recently. the operation and use of data - base management systems has been outside the scope of many scientists' training. It is no use having a user - friendly system if the potential user has no idea of how to make friends with the system. It is only with adequate instruction that the environmental scientist can collect his data in such a way as to make maximum use of such systems. As a result of frustration with existing systems. some environmental s cientists have developed specialised information retrieval systems to handle the data being obtained (AlIen. 1983). The complexity of environmental data types has for many years prevented their full use in land use planning and resource management. Perhaps the first successful attempt at this on a regional basis was the approach of McHarg (1971). which used successive overlays of maps detailing environmental features to highlight areas s uitable for different types of development. This approach has been further refined with the advent of rapid computer processing. and the ability now to handle data based on a variety of points. lines. polygons or rectangles (see. for example. Gates. McCown and Butler. 1977; Kessell. Good and Potter. 1982). The integration of these systems with sophisticated graphics packages can provide the environmental planner or manager with an extremely powerful tool. However. until now. the relative high cost of these systems has precluded their use in all but the largest environmental programs. even though their benefits are obvious to the practising environmental scientist. THE OPERATING PHASE Once a mining or mineral processing operation gets underway. a major function of the
Automation. Mining and th e EI1\'ironlllcllt environmental scientist is to ensure compliance with legislative and licence conditions. In order to achieve this. extensive and sometimes quite sophisticated monitoring systems need to be established. For example. automatic water samplers. working on either a time - or event-based procedure. are commonly found around sites which have a potential to contaminate water resources. However the high apparent cost of such systems often preclude their use in many situations. A further step in automation has been achieved by the introduction of computer controlled real time analytical systems. such as that installed for sulphur dioxide control at Mount Isa. Queensland (Jones. 1980). In this system a network of sulphur dioxide analysers throughout the city continuously analyses the sulphur dioxide concentration in the air. These analysers are regularly interrogated by a central computer. which processes and summarizes the data. presenting it to an operator in such a way as to provide him with a constant picture of sulphur dioxide movement throughout the city. Coupled with real time meteorological and emission data. this enables the operator to control operation of the smelters so that statutory limits are not exceeded. The system also produces summaries for management and government reports. The introduction of similar systems at other smelting complexes for air pollutants other than sulphur dioxide has been hampered to date by the lack of reliable real time analysers for the substances in question. For example. lead-in-air has become a matter for some concern both inside and around lead smelters. but monitoring systems such as that developed at Mount Isa for sulphur dioxide have not been installed. Only recently has a rapid analyser for lead-in- air been developed. but there is still a considerable delay in reporting relatively low levels of lead (but levels which are above the statutory limits) so that the analysers are of limited use. Similarly. fugitive or non-point source air emissions are now regarded as a major problem in smelters. as most other emission sources can be readily identified and controlled. It is still difficult. if not impossible. to easily identify the source of fugitive emissions. although there have been attempts in recent years to use newly developed analytical techniques to do this. Bradley and others (1981) used a combination of scanning electron microscopy and X- ray energy-dispersive and wavelength-dispersive spectrometry to investigate the chemical compositions of airborne particles sampled around a copper smelter. Four types of particles were identified . which could be uniquely associated with different stages of the smelting process. thus allowing calculation of the contribution of each stage of the process to any particulate sample. Harrison and others (1981) examined particle size and chemical composition (by x-ray powder diffraction spectrometry) of workplace dust samples within a pyrometallurgical zinc-lead smelter. These factors were found to be correlated with the smelting operations occurring close to each sampling site and in at least one case a chemical phase specific to a single operation was identified. This was an elemental lead aerosol at the bullion floor of
an Imperial Smelting Furnace plant. However. neither of these techniques are yet able to be used to easily identify the relative contribution of a number of fugitive emission sources to a particulate sample collected around a metallurgical plant. In some open pit mines. particularly those located close to communities. control of blasting noise and vibration is of major concern. At Alcoa of Australia's bauxite mining operations in the Darling Range south east of Perth . an extensive blast noise monitoring program has been established (Delaney. 1982). The development of a computerised blast noise prediction model and the establishment of a radiosonde weather balloon facility have reduced blast induced complaints by a factor of ten. Similar systems are under development at other minesites. but again the lack of robust equipment suitable for extreme Australian conditions limits their efficient utilization. Recent investigations into airborne dust generated by intensive open cut coal mining in the Hunter Valley of New South Wales have been hampered by the complexity of the meteorology and topography. and the difficulty in defining the dust load from anyone mine. The State Pollution Control Commission. the principal regulatory authority. has resorted to a computer model in order to predict the dust generated by new mines in the Valley (Ferrari and Ross. 1983). Although numerical models may appear to be very useful to the controlling authorities. care must be taken that their application is backed up by vigorous testing before being used in a predictive sense. In addition. although seemingly cost efficient through the reduction in labour and analytical costs. models such as this have frequently proved to be prohibitively expensive in terms of computer processing time. Ideally. what we need are simple cost effective methods of monitoring and predicting air pollution which are capable of being widely applied. to both other sites and other mine types. Unfortunately. such tools have still to be developed. In the design of a waste disposal facility. for example a tailing dam. waste products that are toxic. highly reactive or otherwise represent a significant threat to public health. safety and welfare must be isolated from the environment. Complete isolation of these wastes from groundwater resources is not always practicable. particularly when they are disposed of as liquids or in slurry form. The extent of groundwater contamination can be determined by establishing monitoring wells around the disposal facility. and sampling and analysing the groundwater (Humenick. Turk and Colchin. 1980). Mathematical models can then be used to predict the transport of contaminants. and the effectiveness of various control measures. These models can also be used to predict the total length of time that contaminated leachate or seepage will be generated after a disposal facility has been completed. or after rehabilitation has taken place. However. the comments above regarding air pollution models also apply in this situation.
T. P. Fan'e ll
2-1 THE: SHUTDOWN OR REHABILITATION PHASE In the rehabilitation phase of mines. the surface drainage pattern after mining is coming increasingly under scrutiny. In the United States. the Surface Mining and Reclamation Act of 1977 requires that mined sites be regraded back to the original contour and that the hydrologic integrity of surface streams is preserved. This is generally taken to mean that stream networks be returned to as close to a pre - mining configuration as practicable. Post-mining topography can be modelled by using Geographic Information Systems. resulting in a topography that will achieve the design for stream gradients and the concept of original contour (Thames and Rasmussen. 1982). Appropriate stream gradients are computed using runoff-stream flow models. Although requirements in Australia are not as strict as those in the United States. advanced modelling techniques such as these are increasingly being used in mine and waste emplacement design . As the resources available for a rehabilitation program decline after shutdown of a mining operation. remote s ensing and automation can be used to maintain an acceptabl e mo nitoring program (e.g . Ander son and Tanner. 1978). All of the techniques discussed above can play an impo rtant role in ensuring the effectiveness of rehabilitation while at the s ame time keeping costs to a minimum . However. the fault s and problems outlined also add to the uncertainty as to the quality of the information gained . CONCLUSIONS Poor quality control is probably the greatest obstacle to wider use of automation in environmental control of mining and mineral processing . Second to this is the lack of simple yet elegant tools which c an be used by the environmental scientist employed in the mining indu s try. Until this situation is improved. scientists will be loath to drop their tedious but effective manual methods. in favour of the new technology. It must be the role of the electronics engineer. the computer programmer and other specialists to take not e of the environnmental scientists' problems. if their products are to achieve the market penetration they desire. REFERENCES AlIen. N.T . (1983). Worsley Alumina project fauna studies. principles and practice. In Papers of the North Australian Rehabilitation workshop. Bowen. June 1983 . pp . 78-101 . Allison. I. and Morrissy. J.V . (1983). Automatic weather stations in the Antarctic. Aust. Met. Mag .. ll. 71-76 . Anderson. J . E. and Tanner. C.E. (1978). Monitoring of Coal strip Mine Rehabil itat ion. u. S. Environmental Protection Agency. Report No. EPA-600/7-78- 149.
Remote
Bradley. J.P .. Goodman. P .. Chan. I.Y. and Buseck. P.R. (1981). Structure and evolution of fugitive partic les from a
copper smelter. 1208-1212.
Environ. Sci. Technol .• 15.
Christian. C.S . and Stewart. G.A. (1953). General report on survey of Katherine-Darwin region. 1946 . Land Research Series No . 1. CSIRO. Melbourne. Delaney. W. (1982). Meteorological forecasting of blast noise from the Del Park minesite. Proc. The Aus. I.M.M. Conference. Melbourne. Vic .. August 1982. pp. 221-231. Ferrari. L. M. and Ross. I.B. (1983). Monitoring and modelling air quality around mining. smelting and processing operations. In Papers of the Australian Mining Industry Council Environmental Workshop. Hunter Valley. September 1983. pp. 80- 99. Foran. B. and Pickup. G. (1984) . Relationship of aircraft radiometri c measurements to bare ground on s emi - desert landscapes in central Australia. Aust. Rangel. J . 6. 59-68. Gates. W.A .. McCown. B.H. and Butler. K.S. (1977) . A resource data management system. GRASP: Description and documentation of software. IES Report 90. Institute for Environmental Studies. University of Wisconsin- Madison. Harrison. R.M .. Williams. C.R. and O·Neill. I.K. (1981). Characterization of airborne heavy metals within a primary zinc-lead smelting works. Environ. Sci. Technol .. 12. 1197- 1204 . Humenick. M.J .. Turk. L.J. and Colchin. M.P. (1980). Methodology for monitoring ground water at uranium solution mines. Ground Water. 18. 262-273. John. C. D. (1982) . The MRI Weather Wizard climatological system. In Papers of the Australian Mining Industry Council Environmental Workshop. Darwin. September 1982. pp . 163- 167. Jone s. D.G . (1980) . Meteorological aspects of air quality control at Mount Isa. In Papers of the Australian Mining Industry Council Environmental Workshop. Rockhampton. September 1980. pp. 313-336. Kessell. S.R .. Good. R.B. and Potter. M.W. (1982). Computer Modelling in Natural Area Management. Special Publication 9. Australian National Parks and Wildlife Service. Canberra. Laut. P .. Heyligers. P.C .• Keig. G.. Loff1er. E .. Margules. C. and Scott. R.M. (1977). Environments of South Australia Handbook. CSIRO. Canberra. McHarg. I.L. (1971). Design with Nature. Doubleday & Co . . New York. Thames. J.L. and Rasmussen. W.O. (1982). Design of post mine topography to maintain hydrologic integrity of surface streams. Min. Congr. J . . Jan . 1982. 46-50.
!"O l
Automation, Mining and the Environment: Where are we Heading? TOM P FARRELL Technical and Commercia l Services CRA limited, Me lbourne
Ab stract , The role of automation in the environmental management of the various stages of mining projects is discussed, Remote sensing can be useful in the exploration phase, but tends not to have sufficient resolution for individual operations. Automatic samplers, whether for meteorology, air or water, are widely used, but can have operational problems. The environmental scientist, the electronics engineer and the computer programmer must combine in the future to develop products which are applicable, robust and simple to use . Keywords, Computer software; environment control; mining.
data acquisition;
INTRODUCTION
data reduction and analysis;
predicting the inter-relationships both within them and between them and the external environment. As the geologist s were hampered by the vastness of the Australian continent. so too were the natural sc ientist s, It was only in the early 1950's, for example. that the Northern Au s tralian lands cape was extensively studied. but again the problem of scale meant that very general technique s had to be developed (Christian and Stewart. 1953) . Even today. there are vast ar eas of the continent that have had barely a glance by natural scientists ,
Less than twenty years ago, mineral exploration, and the subsequent development and processing of the discovered ore, were the almost exclus ive realm of the geologist, mining engineer and metallurgist. Other professionals, from accountants t o engineers. provided support for those whose task was seen to be the di scovery and ultimate exploitation of a mineral resource. Indeed. some people may even have r egarded their role as dominant over all others. Subsequently , however . we have seen the upsurge of other professions which vie with those "classical" professions for important roles in the industry, Among these are two that are particularly relevant t o thi s symposium the electronics engineer and the environmental specialist .
The result of thi s is , of course. that when confronted by the need t o report on the natural environment of a prospective minesite. the environmenta l scientist is frequently hampered by the lack of information available about the area .
It is the aim of this paper to examine the often compleme ntary roles of these specia li sts in the different phases of a mining operation. and to examine deficient or problem areas where their spec ialities may be used in the future .
In an attempt to overcome this problem. some have turned to satellite imagery to give at least a s mall scale data s et on which to base larger scale interpretation. One of the mos t s uccessfu l examples of such studies has been the seven volume publication "The environments of South Australia" (Laut and others. 1977). whi ch contains the environmental information that was prepared for a study entitled "A feasibility study for an ecological survey of Australia". Beca use of the enormous area invo lved . extensive use wa s made of Landsat imagery for base mapping. Nevertheless. this is still no substitute for detailed on - the - ground inspection; where it is useful is in enabling an initial asse ssment of the relative importance of a particular l andscape or. less conclusively. vegetation type.
THE EXPLORATION PHASE Not so long ago. people s ear c hing for minerals pi c ked up clues simply by walking over the ground and examining it visually. Rocks stained a particular co l o ur, sudden changes in vegetation. material thrown up by burrowing animals - all these could provide evidence of a mineral depos it , Nowadays. the exploration work often starts with images o f the ground obtained by an orbiting s atellite such as Landsat , With computer te chniques. a researcher can analyse the image to l ook f or changes in structures or base geol ogy which may indicate the prese nt of a depos it.
Despite the large advances over re cent year s in the resolution of satel lit e imagery. and subsequent computer enhancement and numerical analysis . ground truthing is still necessary . This important fact is unfortunately sometimes forgotten in the rush to produce elegantly presented publi c ations. or reports for
Similarly, in the past. scientists studying the natural environment reli ed on cove ring the ground on foot or by vehicle. recording the pres ence or absence of plants and animals and 21
T. 1'. Farrell
clamouring regulatory authorities. Two major problem areas immediately spring to mind; firstly. it can easily be forgotten that satellite imagery is comprised of electronic signals and is not photography in the commonly accepted form. Colours are assigned during processing on the basis of the energy reflected from the earth's surface. and the spectral signature of vegetation can vary greatly depending on the season. water avai'lability. or whether it has recently been subjected to stress. for example burning. Thus differences observed on the image may be artefacts and may not represent actual differences on the ground. The second problem area is the scale of such imagery. and consequently the poor resolution obtained. While the most recent Landsat satellite has a resolution of around 70 metres. this still means that small scale features of interest to the environmental scientist cannot be discerned. Although new satellites are being prepared with much better resolution. in the order of 10 metres. satellite imagery will probably still remain best suited for broad scale repetitive inventory. as described by Foran and Pickup (1984). THE FEASI8ILITY STUDY PHASE As the exploration phase passes into the feasibility study phase. environmental studies become more and more site specific. and begin to concentrate on the actual and perceived impacts of a potential mining or mineral processing operation. Two important factors need to be considered at this stage: what data need to be collected and how best to collect them; and how best to organize the data so obtained in order to minimize impacts while. at the same time. monitoring these impacts. It is also at this stage that an Environment Impact Study is produced. In the early stages of feasibility studies. especially for a deposit in a remote location. personnel are not on - site full time. and therefore data collection needs to De organized on a campaign basis or be automated in some way. For basic physical information. e.g. meteorology. this most likely mean the installation of an automatic data aquisition system. For some time small "package" weather stations. which record a variety of meteorological information on paper charts. have been available in Australia. Such systems have proved in the past to be extremely robust and reliable. with the major problems appearing to lie with the timing mechanism or with pens that become blocked or dry out. The latter problem has been overcome to some extent by the introduction of felt-tip pen cartridges. In some high humidity tropical areas there have been problems with charts tearing after becoming saturated with moisture. In addition. chart changing has been a skill which many technicians have lacked. The greatest difficulty with these systems has been the processing of the often voluminous charts obtained from them. Although chart digitising services are becoming more and more available. these are expensive a~d time consuming. Thus. the "second generation" of recording devices - electronic data loggers has appeared. These. powered by batteries and backed up by solar cells. frequently scan a variety of recording instruments and write raw or processed information onto magnetic tape or. more recently. into electronic data storage
modules. Although potentially more reliable than the mechanical systems. many of those currently in use in Australia have been plagued with problems (see for example John. 1982). The most common fault appears to be the sensitivity of electronic systems to environmental extremes. This unreliability of such equipment. coupled with the comparative state-of-the-art nature of it (e.g. most serial numbers are below 100). has led to its use being abandoned at some remote sites. Nevertheless. if these problems can be overcome. such equipment would appear to be the simplest to install and use. Already. a third generation of these automatic weather stations is becoming available - those that transmit signals in real time through geostationary satellites to ground stations. where they are recorded in computer storage for subsequent processing (Allison and Morrissy. 1983) . Once data have been recorded. it should be a comparatively simple matter to read it off the recording medium into more accessible storage in a micro- or mainframe computer. However. in my experience. this is complicated by the absence of a strict industry standard in communication devices. and the appalling unreadability of most documentation. The concept of "user friendly" has certainly not progressed to this level. Although strictly outside the scope of this paper. the subsequent storage and accession of any such data must be important in environmental programs. Until recently. the operation and use of data - base management systems has been outside the scope of many scientists' training. It is no use having a user - friendly system if the potential user has no idea of how to make friends with the system. It is only with adequate instruction that the environmental scientist can collect his data in such a way as to make maximum use of such systems. As a result of frustration with existing systems. some environmental s cientists have developed specialised information retrieval systems to handle the data being obtained (AlIen. 1983). The complexity of environmental data types has for many years prevented their full use in land use planning and resource management. Perhaps the first successful attempt at this on a regional basis was the approach of McHarg (1971). which used successive overlays of maps detailing environmental features to highlight areas s uitable for different types of development. This approach has been further refined with the advent of rapid computer processing. and the ability now to handle data based on a variety of points. lines. polygons or rectangles (see. for example. Gates. McCown and Butler. 1977; Kessell. Good and Potter. 1982). The integration of these systems with sophisticated graphics packages can provide the environmental planner or manager with an extremely powerful tool. However. until now. the relative high cost of these systems has precluded their use in all but the largest environmental programs. even though their benefits are obvious to the practising environmental scientist. THE OPERATING PHASE Once a mining or mineral processing operation gets underway. a major function of the
Automation. Mining and th e EI1\'ironlllcllt environmental scientist is to ensure compliance with legislative and licence conditions. In order to achieve this. extensive and sometimes quite sophisticated monitoring systems need to be established. For example. automatic water samplers. working on either a time - or event-based procedure. are commonly found around sites which have a potential to contaminate water resources. However the high apparent cost of such systems often preclude their use in many situations. A further step in automation has been achieved by the introduction of computer controlled real time analytical systems. such as that installed for sulphur dioxide control at Mount Isa. Queensland (Jones. 1980). In this system a network of sulphur dioxide analysers throughout the city continuously analyses the sulphur dioxide concentration in the air. These analysers are regularly interrogated by a central computer. which processes and summarizes the data. presenting it to an operator in such a way as to provide him with a constant picture of sulphur dioxide movement throughout the city. Coupled with real time meteorological and emission data. this enables the operator to control operation of the smelters so that statutory limits are not exceeded. The system also produces summaries for management and government reports. The introduction of similar systems at other smelting complexes for air pollutants other than sulphur dioxide has been hampered to date by the lack of reliable real time analysers for the substances in question. For example. lead-in-air has become a matter for some concern both inside and around lead smelters. but monitoring systems such as that developed at Mount Isa for sulphur dioxide have not been installed. Only recently has a rapid analyser for lead-in- air been developed. but there is still a considerable delay in reporting relatively low levels of lead (but levels which are above the statutory limits) so that the analysers are of limited use. Similarly. fugitive or non-point source air emissions are now regarded as a major problem in smelters. as most other emission sources can be readily identified and controlled. It is still difficult. if not impossible. to easily identify the source of fugitive emissions. although there have been attempts in recent years to use newly developed analytical techniques to do this. Bradley and others (1981) used a combination of scanning electron microscopy and X- ray energy-dispersive and wavelength-dispersive spectrometry to investigate the chemical compositions of airborne particles sampled around a copper smelter. Four types of particles were identified . which could be uniquely associated with different stages of the smelting process. thus allowing calculation of the contribution of each stage of the process to any particulate sample. Harrison and others (1981) examined particle size and chemical composition (by x-ray powder diffraction spectrometry) of workplace dust samples within a pyrometallurgical zinc-lead smelter. These factors were found to be correlated with the smelting operations occurring close to each sampling site and in at least one case a chemical phase specific to a single operation was identified. This was an elemental lead aerosol at the bullion floor of
an Imperial Smelting Furnace plant. However. neither of these techniques are yet able to be used to easily identify the relative contribution of a number of fugitive emission sources to a particulate sample collected around a metallurgical plant. In some open pit mines. particularly those located close to communities. control of blasting noise and vibration is of major concern. At Alcoa of Australia's bauxite mining operations in the Darling Range south east of Perth . an extensive blast noise monitoring program has been established (Delaney. 1982). The development of a computerised blast noise prediction model and the establishment of a radiosonde weather balloon facility have reduced blast induced complaints by a factor of ten. Similar systems are under development at other minesites. but again the lack of robust equipment suitable for extreme Australian conditions limits their efficient utilization. Recent investigations into airborne dust generated by intensive open cut coal mining in the Hunter Valley of New South Wales have been hampered by the complexity of the meteorology and topography. and the difficulty in defining the dust load from anyone mine. The State Pollution Control Commission. the principal regulatory authority. has resorted to a computer model in order to predict the dust generated by new mines in the Valley (Ferrari and Ross. 1983). Although numerical models may appear to be very useful to the controlling authorities. care must be taken that their application is backed up by vigorous testing before being used in a predictive sense. In addition. although seemingly cost efficient through the reduction in labour and analytical costs. models such as this have frequently proved to be prohibitively expensive in terms of computer processing time. Ideally. what we need are simple cost effective methods of monitoring and predicting air pollution which are capable of being widely applied. to both other sites and other mine types. Unfortunately. such tools have still to be developed. In the design of a waste disposal facility. for example a tailing dam. waste products that are toxic. highly reactive or otherwise represent a significant threat to public health. safety and welfare must be isolated from the environment. Complete isolation of these wastes from groundwater resources is not always practicable. particularly when they are disposed of as liquids or in slurry form. The extent of groundwater contamination can be determined by establishing monitoring wells around the disposal facility. and sampling and analysing the groundwater (Humenick. Turk and Colchin. 1980). Mathematical models can then be used to predict the transport of contaminants. and the effectiveness of various control measures. These models can also be used to predict the total length of time that contaminated leachate or seepage will be generated after a disposal facility has been completed. or after rehabilitation has taken place. However. the comments above regarding air pollution models also apply in this situation.
T. P. Fan'e ll
2-1 THE: SHUTDOWN OR REHABILITATION PHASE In the rehabilitation phase of mines. the surface drainage pattern after mining is coming increasingly under scrutiny. In the United States. the Surface Mining and Reclamation Act of 1977 requires that mined sites be regraded back to the original contour and that the hydrologic integrity of surface streams is preserved. This is generally taken to mean that stream networks be returned to as close to a pre - mining configuration as practicable. Post-mining topography can be modelled by using Geographic Information Systems. resulting in a topography that will achieve the design for stream gradients and the concept of original contour (Thames and Rasmussen. 1982). Appropriate stream gradients are computed using runoff-stream flow models. Although requirements in Australia are not as strict as those in the United States. advanced modelling techniques such as these are increasingly being used in mine and waste emplacement design . As the resources available for a rehabilitation program decline after shutdown of a mining operation. remote s ensing and automation can be used to maintain an acceptabl e mo nitoring program (e.g . Ander son and Tanner. 1978). All of the techniques discussed above can play an impo rtant role in ensuring the effectiveness of rehabilitation while at the s ame time keeping costs to a minimum . However. the fault s and problems outlined also add to the uncertainty as to the quality of the information gained . CONCLUSIONS Poor quality control is probably the greatest obstacle to wider use of automation in environmental control of mining and mineral processing . Second to this is the lack of simple yet elegant tools which c an be used by the environmental scientist employed in the mining indu s try. Until this situation is improved. scientists will be loath to drop their tedious but effective manual methods. in favour of the new technology. It must be the role of the electronics engineer. the computer programmer and other specialists to take not e of the environnmental scientists' problems. if their products are to achieve the market penetration they desire. REFERENCES AlIen. N.T . (1983). Worsley Alumina project fauna studies. principles and practice. In Papers of the North Australian Rehabilitation workshop. Bowen. June 1983 . pp . 78-101 . Allison. I. and Morrissy. J.V . (1983). Automatic weather stations in the Antarctic. Aust. Met. Mag .. ll. 71-76 . Anderson. J . E. and Tanner. C.E. (1978). Monitoring of Coal strip Mine Rehabil itat ion. u. S. Environmental Protection Agency. Report No. EPA-600/7-78- 149.
Remote
Bradley. J.P .. Goodman. P .. Chan. I.Y. and Buseck. P.R. (1981). Structure and evolution of fugitive partic les from a
copper smelter. 1208-1212.
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Christian. C.S . and Stewart. G.A. (1953). General report on survey of Katherine-Darwin region. 1946 . Land Research Series No . 1. CSIRO. Melbourne. Delaney. W. (1982). Meteorological forecasting of blast noise from the Del Park minesite. Proc. The Aus. I.M.M. Conference. Melbourne. Vic .. August 1982. pp. 221-231. Ferrari. L. M. and Ross. I.B. (1983). Monitoring and modelling air quality around mining. smelting and processing operations. In Papers of the Australian Mining Industry Council Environmental Workshop. Hunter Valley. September 1983. pp. 80- 99. Foran. B. and Pickup. G. (1984) . Relationship of aircraft radiometri c measurements to bare ground on s emi - desert landscapes in central Australia. Aust. Rangel. J . 6. 59-68. Gates. W.A .. McCown. B.H. and Butler. K.S. (1977) . A resource data management system. GRASP: Description and documentation of software. IES Report 90. Institute for Environmental Studies. University of Wisconsin- Madison. Harrison. R.M .. Williams. C.R. and O·Neill. I.K. (1981). Characterization of airborne heavy metals within a primary zinc-lead smelting works. Environ. Sci. Technol .. 12. 1197- 1204 . Humenick. M.J .. Turk. L.J. and Colchin. M.P. (1980). Methodology for monitoring ground water at uranium solution mines. Ground Water. 18. 262-273. John. C. D. (1982) . The MRI Weather Wizard climatological system. In Papers of the Australian Mining Industry Council Environmental Workshop. Darwin. September 1982. pp . 163- 167. Jone s. D.G . (1980) . Meteorological aspects of air quality control at Mount Isa. In Papers of the Australian Mining Industry Council Environmental Workshop. Rockhampton. September 1980. pp. 313-336. Kessell. S.R .. Good. R.B. and Potter. M.W. (1982). Computer Modelling in Natural Area Management. Special Publication 9. Australian National Parks and Wildlife Service. Canberra. Laut. P .. Heyligers. P.C .• Keig. G.. Loff1er. E .. Margules. C. and Scott. R.M. (1977). Environments of South Australia Handbook. CSIRO. Canberra. McHarg. I.L. (1971). Design with Nature. Doubleday & Co . . New York. Thames. J.L. and Rasmussen. W.O. (1982). Design of post mine topography to maintain hydrologic integrity of surface streams. Min. Congr. J . . Jan . 1982. 46-50.