Environmental and Engineering Geoscience; August 2007; v. 13; no. 3;
p. 270-272; DOI: 10.2113/gseegeosci.13.3.270
© 2007 Association of Engineering Geologists
Mining and Its Impact on the Environment by Fred G. Bell and Laurance J. Donnelly
Allen W. Hatheway1
1 10256 Stoltz Drive, Rolla, MO
Mining, since its origin, generally has been predicated and conducted on the principles of maximum extraction consistent with minimally acceptable factors of safety for the mine workers. In most cases, the ore or other mineral of value was recovered from areas that were generally unpopulated, and the commodity was shipped to other locations for further processing into the raw material of industry. The miners were pleased to have work, wages, and benefits. Vast fortunes were accumulated by the interests that financed and promoted the mining. For most of its history mining did not have to recognize the long-lasting environmental impacts of its works because the local population was the direct beneficiary of the mining.
In Britain, however, with the appearance of Watt's steam engine in the late 18th century, the courses of mining and population began to merge as locally-mined coal fueled the steam engines that powered the industries that made use of native iron. By the 1820s, Britain and portions of central Europe had the same industrial collisions of mining and heavy population. From then on, the detriment of mining to the land began to create noticeable impacts on the environment in which considerable numbers of people lived, breathed, and consumed natural waters, all of which were subject to negative impacts.
Generally speaking, society has been silently tolerant of the damaging impacts of mining, but with the advent of the so-called "environment era" voices have more and more decried the despoliation of mined ground. Of course, to bring the situation full circle, we must realize that it has been the financial benefits of mining granted to society that have benefited the increased intellectual and scientific awareness that now no longer tolerates mining impacts.
To date, there has been no comprehensive, single-source summarization of the systematic nature of mining impacts on the environment. There is no doubt that this treatment has been needed, and it is a wonder that Bell and Donnelly, in meeting this need, have themselves come forth some 35 years after the debut of the Environmental Era. One obvious reason is that the subject has been generally unpopular with the mining industry, which has had to adapt to environmentalists, most of whom have benefited greatly from the fruits of mining. Second, the industry was not about to willingly move into a posture of environmental mitigation and restoration. This has changed, and mining companies are now major sponsors of environmental remediation research.
Taken together, the past 35 years have set the stage for which Bell and Donnelly, with their obvious qualifications, could poise themselves to investigate today's mature situation of an environmentally-conscious mining industry. The authors have built their assessment by explaining the physical processes of mining as they affect the environment of the host ground and of the ground upon the mineral process wastes are disposed. They accomplish this in 10 chapters, each of which offers the reader a description of the situation and information related to appropriate environmental response.
- Chapter 1: Introduction: The mineral extraction situation as it is in today's (post-1970) environmental, legal and regulatory context is discussed. The authors further recognize the protective and remedial means employed by today's environmentally-conscious minerals industry and how modern geologists and engineers now deal with derelict, pre-environmental-era workings and their various residuals and wastes. The stringent requirements for new extraction ventures are introduced, i.e., when and where they are now allowed by society in the developed world, as well as in more remote areas, worldwide.
- Chapter 2: Subsidence: Massive subsurface extraction is shown to have left potentially unstable underground voids, the instability of which only worsens with time and which is due to mine layout and inappropriate extraction practices. As usual, Bell pays attention to case examples documented from the literature, generally including sufficient numerical quantification to give the reader an absolute sense of magnitude. The authors show how hazard zoning can be applied to dangerous situations as interim mitigation, before funding of more absolute, physical mitigation measures, and introduce concepts of engineered remediation.
- Chapter 3: Longwall Mining: Here the authors argue that, for sheer volume of ground undergoing subsidence, the longwall-panel extraction method is a significant hazard. They show how subtle, large-area subsidence can damage modern infrastructure and how this damage has a unique long time-path to incremental failure. Donnelly's own practical experience provides a useful classification of the observable surface features indicating subsidence reactivation of ancient bedrock faults in the mine overburden rock.
- Chapter 4: Metalliferous Mining: Leaving behind the issues associated with coal mining, the authors then discuss derelict metal mines. It would not be possible to treat the infinitude of subsidence scenarios with the precision of Chapter 3; however, the reader is provided with an insight into the need to define the geometry of the mined ore deposit and with three case histories on how damage can be mitigated.
- Chapter 5: Abstraction of Fluids: The book now moves from more local environmental impacts to larger scale problems. Groundwater, geothermal vapor, brine, oil, and gas are the fluids considered, although the groundwater dissolution in karst and the infiltration of previously-pumped mine-water surfaces are also addressed. In this case, the volume of ground so-affected jumps logarithmically from those cases considered in the previous chapter, as does the general imprecision associated with characterization of the target ground. This chapter introduces the theme of mining-related pollution, with the focus shifting from physical damage to geochemical contamination.
- Chapter 6: Quarrying and Surface Mining: Issues of slope stability take precedence and are shown to be highly dependent on geologic structure, the effects of gravity, and the presence and movement of various form of groundwater discharge along the slope faces. Blasting is introduced, and its potential for causing damage to nearby buildings and other structures is documented. The authors then treat alluvial mining and dredging and move into the huge category of sand and gravel mining, and management of their slope stability and hydrogeological impacts. The chapter concludes with the appropriate methods for closure of existing aggregate deposits and for reclamation of derelict pits, with two case histories in illustration.
- Chapter 7: Waste Materials: Once more the book changes complexion by addressing contamination associated with mining. As mining waste is comminuted or otherwise broken and sometimes screened for particle separation, Bell's fascination with earth-material properties is on display. The reader is shown how to classify and assess the pollution-potential of mining wastes in terms of surface-area leachability and the potential for slope instability and erosion. Because of the need to process most mining waste with water and the production of tailings slurries, this chapter points out the potential hazard of pore pressures within large piles (and sometimes dammed) of waste rock.
- Chapter 8: Mine Effluents: Most mine waste, except some overburden spoil, may contaminate local waters because of the presence of sulfides and their role in acidification. Furthermore, the dissolution of the metal sulfides results in the leaching of heavy metals from the spoil. This chapter addresses these environmental geochemical issues, and two case histories are provided. Methods of prediction, control, and mitigation are also included.
- Chapter 9: Dereliction and Contamination: The authors then treat mill sites used for ore processing separately from the mine workings and advise on the importance of site characterization. Further information is presented concerning environmental contamination by the more common heavy metals. The remainder of the chapter deals with some of the methods by which toxic waste sites can be remediated, given proper characterization. The message is reinforced with three case histories.
- Chapter 10: Other Problems: A final general chapter deals with special environmental problems such as spontaneous fires, release of mineral gases, induced seismicity, acid drainage and heap-leaching pollution, mineral dusts, and mining-induced landslides.
In summary, Bell and Donnelly complement one another in nature and breadth of experience. Bell is known for his command of the literature, whereas Donnelly has had a rigorous career of practice in and on the mines and so adds the dimension of environmental awareness upon the mining industry. The book is well illustrated with images of relevance to the text, and useful maps, vertical sections, and drawings are provided, along with appropriate references at the end of each chapter. The reader will be well served who makes use of the text to identify physical and chemical parameters and geologic influences that may be present for individual projects. This reviewer envisions, as a special benefit, the potential use of the book to help identify and tabulate special considerations for presentation in competitive consulting-project proposals, whereby the client is shown the special understanding of the reader as the best contender to conduct the contract work.
REFERENCES CITED
Bell, F.G, and Donnelly, L.J, 2006, Mining and its Impact on the Environment, Taylor & Francis Group London. 547 ISBN 0-415-28644-1, approximately $145.00.
Copyright © 2009 by Association of Engineering Geologists
