Chadwick / Highton / Lindman Environmental Impacts of Coal Mining & Utilization

A Complete Revision of Environmental Implications of Expanded Coal Utilization
1. Auflage 2013
ISBN: 978-1-4832-8630-3
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 358 Seiten

As coal is considered as a substitute for other fuels, more serious attention is being given to the environmental impacts of the whole coal fuel cycle: mining, transport, storage, combustion and conversion. This volume presents an up-to-date account of these environmental impacts and the recent developments to combat and control them. A feature of the book is the way in which it discusses not only the experience and developments in North America and Western Europe but also presents much information made available for this study on the developments in the socialist countries of Eastern Europe.

Autoren/Hrsg.

Chadwick, M. J.

Highton, N. H.

Lindman, N.

Leseproben

2

Land Disturbance and Reclamation after Mining

Publisher Summary

This chapter discusses land disturbance and reclamation after mining. It presents a classification of land disturbance because of coal mining that is adapted from a more general and comprehensive classification of Motorina and Ovchinnikov and Bauer and Weinitschke. Land disturbance because of coal mining is classified into two groups: (1) land disturbed by surface mining (strip-mining and open-pit mining) and (2) land disturbed by underground mining. The changes in the environment effected by the coal industry are so profound that often no natural recovery of disturbed landscapes can occur. Land reclamation has emerged as a method of countering the negative after-effects of extracting coal and other minerals. It is also a comprehensive interdisciplinary subject that covers the problems of landscape redevelopment and the restoration of its productivity, ecological integrity, and economic and aesthetic value. The chapter further highlights six main uses of reclaimed land that depend on natural and socio-economic factors of the locality. Framework of land reclamation requirements, developments in mining technology and land reclamation, progress in land reclamation, and the economics of reclamation are also analyzed in the chapter.

1 Introduction

2 Classification of Mining Land Disturbance

3 Land Reclamation

3.1 Reclamation Objectives and Methods

3.2 Framework of Land Reclamation Requirements

3.3 Developments in Mining Technology and Land Reclamation

3.3.1 Strip-mining techniques

3.3.2 Improvements in site engineering technology

3.3.3 Improvements in surface soil treatment

3.3.4 Land-use efficiency improvements

3.3.5 Improvement of underground mining waste reclamation

3.4 Progress in Land Reclamation

3.4.1 General considerations

3.4.2 Land disturbed by surface mining

3.4.3 Land disturbed by underground mining

4 The Economics of Reclamation

5 References

1 Introduction

Irrespective of the actual methods of coal mining being used, mining processes unavoidably bring about land-surface disturbances, and increased mining for expanded coal supplies will inevitably lead to extended land disturbances. Such disturbed land tends to create a negative effect on the surrounding environment and reduces its economic value.

The character of the disturbance depends upon the disposition of the mined strata, and upon the methods used to mine them (Fig. 2.1). Continued improvement of coal-mining methods is associated with the exploitation of deeper coal seams (below 1000 m in deep mining operations and a few hundred metres in surface or strip-mine operations). Generally speaking, progress in mining has led to greater use of open coal extraction methods which produce larger-scale disturbances on the earth’s surface. At the same time, research and development has provided greatly improved engineering and biological methods of landscape reclamation.

FIG. 2.1 Land disturbance by mining: A-open pit deposit deeply dipping; B-open pit with medium dip to deposit; C-open pit with horizontal deposit; D-conventional area strip-mining; E-contour strip-mining of deeply dipped deposit.

Although dramatic changes in landscape may sometimes occur as a result of open mining, underground coal extraction on occasion causes such gross land disturbance that reclamation runs into much greater difficulties and costs than in open mining. If geographical, social and other conditions are similar, such land characteristics as the physical and chemical properties of the rocks and soil in the rooting zone, site permeability and moisture content predetermine the method and technology of the reclamation required. Therefore, study and classification of such properties of disturbed substrates are considered as very important.

2 Classification of Mining Land Disturbance

The following classification, of land disturbance due to coal mining, is adapted from a more general and comprehensive classification of Motorina and Ovchinnikov (1975) and Bauer and Weinitschke (1973). The classifications of Motorina and Ovchinnikov (1975) include one based on relief features and another on overburden characteristics. Although designed for the USSR, they can be adapted for other countries.

1. Land disturbed by surface mining (strip-mining and open-pit mining).

1.1. Open-pit mining disturbance.

1.1.1. Terraced excavations usually over 30 m deep; deposit usually dipped at >30°; overburden stored externally (Fig. 2.1A).

1.1.2. Terraced excavations over 10 m deep; deposit usually 8–30°; most over-burden stored externally (Fig. 2.1B).

1.1.3. Terraced excavations usually 10–30 m deep with deposit dipped at 8°; some internal storage of overburden (Fig. 2.1C).

1.2. Strip-mining disturbance.

1.2.1. Area strip-mining of horizontal deposits relatively near the surface (Fig. 2.1D).

1.2.2. Contour strip-mining of horizontal or steeply dipped deposits in mountainous regions (Fig. 2.1E).

2. Land disturbed by underground (deep) mining.

2.1. Land subsidence.

2.1.1. Canyon subsidence caused by working medium or thick seams that dip steeply (>45°).

2.1.2. Terraced subsidence resulting from the working of seams that show 27–45° dipping and where the land surface slopes.

2.1.3. Bowl or cirque-type subsidence caused by the working of medium or thick seams dipping up to 27°.

2.1.4. Trough-type subsidence resulting from mining low and medium thickness, horizontal or slightly inclined seams; appear like natural depressions.

2.2. Surface waste deposits associated with pitheads.

2.2.1. Plateau-shaped tips resulting from single- or multi-level tipping from road or rail transport.

2.2.2. Crest-shaped tips resulting from cableway dumping.

2.2.3. Conical tips resulting from skip or tip-wagon dumping.

Further detailed consideration of surface mining disturbance is given by Grim and Hill (1974).

3 Land Reclamation

3.1 Reclamation Objectives and Methods

The changes in the environment effected by the coal industry are so profound that often no natural recovery of disturbed landscapes can occur. Land reclamation has emerged as a method of countering the negative aftereffects of extracting coal and other minerals. Land reclamation is also a comprehensive interdisciplinary subject which covers the problems of landscape redevelopment and the restoration of its productivity, ecological integrity and economic and aesthetic value.

Disturbed lands constitute a form of environmental damage produced by the mining industry. If reclamation can be included in the production process, the mining industry could become, given a reasonable time-span, something near a “closed-cycle” industry producing no wastes, However, some overriding climatic factors may result in permanent losses, or the need for continued inputs to the system. This would be true, for example, in very high-rainfall or semi-arid regions respectively.

At the present time land reclamation has to be implemented sequentially (Motorina and Ovchinnikov, 1975). The first step involves planning, followed by research and development. The second step is site preparation for a specific use, consisting of earth-moving and shaping of the surface, water regime control and sometimes the application of productive layer, like topsoil or organic material on the surface. The third step entails biological reclamation which will allow the development of a restored site or landscape. The goal of the third step is to restore fertility and biological productivity to the disturbed land. The six main uses of reclaimed land are as follows, and depend on natural and socio-economic factors of the locality:

(1) agriculture (arable land, orchards, meadows or grazing land);

(2) forestry (commercial or non-commercial forests);

(3) recreation (recreation zones, parks, or public open space);

(4) water use (fishing, swimming, boating...