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Charging for the waste dumping of open-pit metal mines
Mineral
Journal of University of Science and Technology Beijing Volume 13, Number 6, December 2006, Page 481
Charging for the waste dumping of open-pit metal mines Yunbing Hou, Zhaoxiang Zhang, Haifeng Duan, and Liming Xue School of Resources and Safety Engineering, China University of Mining & Technology (Beijing), Beijing 100083, China (Received 2006-02-03)
Abstract: Based on the externality theory and the environmental value theory, the hypothesis of charging for waste dumping of open-pit metal mines was put forth. The charging methods were designed according to the characteristics of waste dumping of openpit metal mines, including charging based on the dumping amount of the total waste, multi-charging factors, exceeding standard punishment charging, and so on. The main charging parameter is based on the dumping area rather than the total amount of waste dumping. The charging model of waste dumping of open-pit mines was formulated, and the charging rate was divided into two parts, i.e., the standard charging rate and the differential charging rate. The standard charging rate was derived using the equilibrium dynamic model, whereas the differential one was obtained by establishing the fuzzy synthesized evaluation model,
Key words: open-pit metal mine; waste dumping; charging pattern; basic charging rate; differential charging rate
1. Introduction
and the reclamation percentage has reached 92% [5-61.
The problem with regard to the extent of the area occupied by waste dumping has been receiving considerable attention in recent years. The total area occupied by mining has reached approximately 5 8 6 ~ 1 0m2 ~ and the destroyed area is 1 5 7 ~ 1 m2, 0 ~ an annual increase by 4x108 m2 [l-41. Mined ore or product from open-pit mines is approximately 30% of the total amount in China. The average destroyed land area is about 7x 106-1OOx lo6 m2 per year, and the accumulated stripped waste of open-pit mines has reached 11.0x109 t. Hence, the total destroyed area is 1 6 7 8 2 ~ 1 m2 0 ~ from 1949 to 2001, and on an average, the height of the dumped waste dump is 22 m.
The hypothesis of charging for waste dumping of the open-pit metal mine is put forth, and the calculation model of charging rate is formulated in this article, considering the special mine environment and referring to the measures taken by the countries all over the world [7].
In USA, waste dumping is regulated by a strict environmental control resources exploitation strategy rather than an “efficient pollution level” put forth by Pigou. As a nation that abounds in mineral resources, Australia considers land reclamation as a precondition to allow the right to exploit mines and establishes the principle of prevention first according to “National Ecological Sustainable Strategy” issued by the government. Germany pays much attention to mine environmental prevention, particularly to open-pit mines, and some local governments prohibit open-pit mine exploitation through legislation. The waste dumping is temporarily restricted to the outside of the stope, and later the mining pit should be filled and leveled up by discarding rocks. The land of the mine must be restored Corresponding author: Yunbing Hou, E-mail: houyunbing20W@ 163.~0111
2. Objective It is impossible to totally regain the past physiognomy and land utility after mine exploitation has been completed. Restoring all of the occupied and destroyed land can and should be done, which is a primary objective with respect to environmental protection. And the standard of quality of reclamation can be implemented according to soil environment quality standard. The objective of charging for mining waste dumping is to decrease the occupied land area by increasing the height of the dumped waste and to reduce the amount of waste dumping by reducing the production amount of the ores. The latter one rather than the elimination of waste dumping is the main function of the Pigou tax. Mining waste dumping has distinct characteristics compared with other pollutants, and the wastes that occupy the land are the main source of environmental pollution. The occupied area of the waste dumping is not only relevant to the amount but also to the height of the waste dumping. The occupied area of the waste dumping can either be increased or decreased by ra-
482
tionally adding or reducing the height of the waste dumping without charging its amount.
3. Charging pattern of the mining waste dumping The standard pattern of the charging for waste dumping is to ascertain the standard of the charging according to the expected function, charging gist, and controlled pollutant amount [8]. With respect to the charging function, there are mainly three charging patterns of waste dumping including stimulating, financing, and the mixed patterns; with respect to the charging gist, there are three patterns including charging according to the total amount, concentration, and medium; with respect to controlling pollutant and factors, there are three patterns including single factor, multi-factor and mixed patterns; there are five patterns including exceeding standard and within standard (concentration standard of the pollutant), exceeding and within permit (license with respect to the extent of pollution), and exceeding both standard and permit patterns if classified by the relationship between the pollution charging standard and environment standard. A total of 135 charging patterns can be obtained by permutation and combination of the patterns listed above [8]. The objective of the charging for waste dumping of the open-pit mine is to promote mine corporations to occupy less land and try to implement land reclamation earlier and ultimately restore natural environment. Therefore, when the method and standard of the charging for waste dumping is established, the fact that whether it can have a good stimulation function to the enterprises must be considered. Furthermore, in establishing the charging patterns, the financial function must be considered because financial shortage is the main cause of the low percentage of land reclamation rate. Therefore, the stimulation of decreasing pollution and finance are the basic principles for establishing the policy of charging for waste dumping.
J. Univ. Sci. Technol. Beijing, Vobl3,N0.6, Dec 2006
waste dumping has no unique standard. Charging according to the amount of waste dumping is unequal and disadvantageous to control pollution. This charging pattern is only a financial means and can neither serve as an incentive to improve the environment nor achieve the aim of improving the environment. Charging based on the total amount of the waste dumping by mining can be accepted easily by mines. However, it cannot stimulate mining corporations to reduce their pollution. According to the externality theory, to maximize their profit, mine corporations will control the production and waste dumping within an effective level when pollution tax is based on the total waste dumping. Therefore, charging for waste dumping can reduce ores or waste dumping. The decrease in the amount relies on the fluctuation of the demand of the ores in the market. If a kind of medium that is not only closely related to the amount of the waste dumping but can directly influence the objective of pollution control or reduction can be found, then charging based on this medium can be feasible. In fact, the waste dump occupies and destroys land and changes the natural scenario of the land, thus bringing out maximum damage. The objective of controlling or reducing the amount of the waste dumping caused by mining is achieved through controlling the extent of the area of the occupied land, while simultaneously controlling the time of occupancy. The ultimate objective of charging for waste dumping is to reduce the extent of land occupied by waste land and to facilitate earlier restoration of land. Accordingly, considering the extent of occupied land and the length of occupied time as the medium of charging is feasible and effective.
Charging according to “concentration” can be understood as the difference in heavy metal content and radioactivity intensity of the mining waste dumping.
With respect to controlling pollutant and factors, there are three charging patterns including single factor, multi-factor, and mixed patterns. Besides occupying the land, the waste that is dumped from mining can also bring about pollution such as heavy metal, radioactivity, and powder diffusion. Therefore, when the charging method is established, many factors should be fully considered.
In the past, the ore production amount was the main factor in the tax and charging such as resource tax, resource compensation charging, and the environment ecology compensation charging. However, the area occupied by mining waste dumping cannot be directly calculated by the production amount of ores because the large difference between ores distributing condition and the discrepancy of stripping-to-ore ratio can range from 2 to 15, and the other reason is that the height of
To implement the charging exceeding standard or permit, the first step is to determine all kinds of environmental standard. Constructing a standard amount of the waste dumping is impossible owing to the limit of the stripping-to-ore ratio. The feasible method is to determine a height standard (or discharging ores inside the stope) to reduce the occupied area, and to restore the land ahead of schedule, thereby shortening the length of the occupied time. Therefore, the standard is
Y.B. Hou et aL, Charging for the waste dumping of open-pit metal mines
483
still the area and length of time. Moreover, a comprehensive standard can be established and the charging for extra waste dumping will be imposed when the dumping exceeds the standard that is established.
mation fare of unit area is u , the forest planting fare of unit area is v, if the amount of the charging can just compensate the reclamation and forest planting fare, there is
4. Determination of the charging rate of waste dumping
c =(u+v)s
The charging rate is the primary step in the implementation of the charging for waste dumping.
4.1. General calculation model of the charging rate of waste dumping The objective of charging for waste dumping is to internalize all of the exterior damage resulting from the occupied land of waste dumping. To identify the purpose of charging and achieve the final objective with regard to environment protection, the charging rate of waste dumping can be divided into two parts: (1) the basic charging rate and (2) the differential charging rate. The charging imposed according to the basic charging rate is mainly used to reclaim the destroyed land and plant trees. So this reclamation should be introduced into the occupied area. The charging imposed according to the differential charging rate is mainly used to compensate for the pollution resulting from powder, carbon loss, radioactivity, and heavy metal, and because such pollution is proportional to the area occupied, the differential charging rate should be based on the basic charging rate and the former should be modified as a coefficient. The differential charging rate should be determined by the method of fuzzy evaluation based on the degree of environmental destruction. The total charging rate can be obtained by
P =P 1+P2
(1)
where p is the total charging rate, Wm2; p , the basic charging rate, Wm2;andp, the differential charging rate, Wm2.
4.2. The basic charging rate of waste dumping Suppose there is a mine where the basic charging of waste dumping is c, the area it occupied is s, the recla-
(2)
where c is the basic charging rate of waste dumping, Y ; s the area occupied by waste dumping, m2; u the reclamation fare of unit area, Wm2;v the forest planting fare of unit area, U/m2. The reclamation and forest planting fare can be obtained by financial budget. Hypothetically there are k working procedures in reclamation land and there are 1 working procedures in forest planting. u and v can be calculated by the following formula: 1
k
u=-&,
v=cvj
i=l
(3)
j=1
where u, is the fare of unit area of reclamation procedure i, Wm2; vi the fare of unit area of forest planting procedure j , Wm2. Then we have I
k p1
(4)
=u+v=cu;+cvj i=l
j=1
Eq. (4) is a static model without considering inflation and consistent with the tax and charging policy implemented by the nation. Such charging policy will result in the charging rate of waste dumping lower after a while. To solve such problem the dynamic equilibrium model and standard optimum model will be better. Suppose the service life of a mine is n, the inflation rate is 9, Eq.(4) can be modified to
[
I
p1 =(l+p)"-'X u ; + c v j j=1
)
(5)
If the time value of money is considered, because the area occupied is different from one year to another, there is
[i + c 'i I
(1 + p),-l
PI =
vj s
ui
(i=l
j=1
),
(1+p)"-1s1+(1+p)"-2s2+...+(l+p)"-'s, +...+ s,
where p is the bank interest rate; s, the area occupied in the year t , m2. Eq. (6) is the dynamic charging rate of reclamation in the year during which the exploitation is completed. PI is not only related to the cost of land reclamation and forest planting but also to the service life of mines, the inflation rate in a certain period, the bank
interest rate, and area occupied annually. The dynamic charging rate is related to the area occupied annually and the statistical area can only be obtained after the exploitation is completed. This problem can be transformed into another one: assume that the area occupied is equal from one year to another, that is
J. Univ. Sci. Technol. Beging, voLz3, N0.6,Dec 2006
484
spective patterns. Suppose the synthesized evaluation coefficient of mine i is bi ( O I b i 51, i = l , 2 ; . . , m ) ,
sI=sz=s3=*--=s,,then there is
P1=
(1 + p y - l
+ (1+ g 2 +. ..+ (1+gr + +1
(7)
and if the basic charging rate is pl, then the differential charging rate of mine i is
** *
4.3. The differential charging rate of waste dumping (1) The synthesized index system of charging for waste dumping.
After the analysis of all kinds of factors that influence the charging rate base of waste dumping, the indices can be classified into three categories as economic, environmental, and geological mining index:
1) Economic index, which comprises: production scale, total mine investment, unit mineral ore price, unit mineral ore exploitation cost, unit rock exfoliation cost, and return on investment. 2) Environmental index, which comprises: CaF content, pollution caused by radioactivity, pollution caused by heavy metal, pollution caused by silicon in mineral powder, carbon content of occupied land, sulfur and phosphor contents, and other pollution. 3 ) Geologic and mining technology index, which comprises: quality of minerals, rock-discharging mode, exfoliation ratio, smelting quality, exploitation quality, geological reserve, and quality of processing.
(2) Formulating the synthesized valuation model.
PZi
=
0.4 I bi < 0.6
(9)
( 3 ) Application of the differential charging rate model. Appendix 1 is the statistics of the mines evaluated. Appendix 2 is the results of the differential charging rate of the mines. The result shows that the differential rate can reveal the specific conditions of the mines because the economical, environmental, and geological mining conditions are all considered. The stripping rate of Western mine has reached 10 t/t and it causes radioactivity and fluorine pollution; therefore, its toll is comparatively high; Baiyun ebo metal mine also causes radioactivity pollution, but it applies belt transportation so the charging rate is in a middle level.
5. Conclusion
matrix; R denotes the fuzzy relation called evaluation index subjection degree matrix; B is the synthesized
A large amount of land is occupied by waste dumped out of open-pit metal mines, which results in damage to the environment and people residing in areas close to the mines. If the policy of charging for waste dumping can be implemented, the problem financing for land reclamation can be solved and the mines can be stimulated to increase the height of waste dumping and to take measures to reclaim land ahead of schedule, thereby reducing the expense on waste dumping and protecting the natural environment. The policy of charging for waste dumping can also promote such green waste dumping pattern as dumping inside pit and using belt transportation. The application of green waste dumping style can bring about a novel innovation of techniques of waste dumping of open-pit metal mines.
evaluation result matrix; and bi denotes the evaluation result of mine i.
References
Hypothetically, if there are m evaluation mines and n evaluation indices, then there is a fuzzy evaluation relation between evaluation events and evaluation indices:
n
where Olaill, X u i = 1; A is the weight coefficient i=l
( 3 ) Determining the differential charging rate. The differential charging rate can be determined by the fuzzy synthesized evaluation. Different open-pit mines can be divided into different charging patterns. The differential charging can be imposed by their re-
[ 11 China Mining Association, China Mining Statistical Year-
book 2002 (in Chinese), Geological Press, Beijing, 2002. p.365. [2] Q.Y. Li, Influences of mineral resource exploitation on environmental quality in China (in Chinese), China Min., 11(2002), No.2, p.47.
Y.B. Hou et al., Charging for the waste dumping of open-pit metal mines [3] H.L. Shi, Review of the research of the ecological environmental protection in mining districts (in Chinese), Met. Mine, 2000, No.9, p.41. [4] F. Zhao, Sudy on the development of China's mineral resources and pollution control (in Chinese), China Min., 12(2003),No.6, p.8. [5] D. Pearce and R. Turner, Economics of Natural Resources and the Environment, Harvester Wheatsheaf,London, 1990, p.12.
485
[6] OECD, Managing the Environment: The Role of Economic Instrument, OECD, Paris, 1994, p.36. [7] H.F. Duan, Study on the Pollution Charge on the Waste Rock in Strip Iron Mine and Impact to the Exploitation [Dissertation] (in Chinese), China University of Mining & Technology, Beijing, 2004, p.26. [8] J.T. Yang, The Reform and Design of Pollution Chargings System in China, China Environmental Science Publishing House, Beijing, 1998, p.120.
Appendix 1. Statistics of the mines evaluated Mines evaluated Name of evaluation index
Economic indices
Baiyun
Heinao-
Gongyi-
Sanhe-
Huang-
ebo
bao
ming
ming
gang
Production scale / lo5 t
loo0
150
200
400
500
Total investment amount /Y 10'
16
2.8
3.2
2.2
Unit mineral ore price / @.t-')
100
140
130
43
78
85
Unit mineral ore exploitation cost I (u t-1)
Environmental
Damao
Damao
west
north
50
800
300
6.5
1.2
14
5.2
110
145
135
95
90
67
48
54
67
58
Guying
Unit rock exfoliation cost I ( u d )
5.8
4.2
3.8
5.5
4.3
6.2
4.8
5
Total occupied area / l@ m2
1568
420
220
340
458
120
4790
340
CaF content
more
less
less
less
medium
medium
more
more
Pollution of radioactivity
more
less
less
less
less
less
more
medium
Pollution of heavy metal
less
less
less
less
less
medium
more
medium
medium
medium
medium
more
more
less
more
more
Carbon content of occupied land
less
medium
medium
medium
more
medium
less
less
Sulphur and phosphor content
more
less
less
medium
medium
more
more
more
Pollution of silicon in mineral
indices
Geologic and mining
Other pollution
medium
medium
less
less
medium
less
more
more
Quality of minerals / %
45
50
41
35
37
43
34
37
Transportation style
railway
truck
truck
truck
railway
truck
Exfoliation ratio / (t.t-')
2.6
1.5
2.2
3.2
2.3
1.1
Smelting quality of minerals
bad
excellent
good
good
good
good
bad
bad
Quality of exploitation
easy
difficult
medium
medium
medium
medium
difficult
difficult
Geological reserve / lo8t
3
0.5
0.8
1.2
0.6
0.5
8
0.5
Quality of processing I %
32
36
34
35
33
35
32
33
technology indices
adhesive tape 10.5
truck 6
Appendix 2. Results of the differential charging rate of the mines Mine Charging
Baiyun ebo
Heinaobao
Gongyiming
Sanheming
Huanggang
Guying
1.000
0.5798
0.5783
0.5925
0.6104
0.607 1
Damao
Damao
west
north
2.1343
2.01 1
Journal of University of Science and Technology Beijing Volume 13, Number 6, December 2006, Page 481
Charging for the waste dumping of open-pit metal mines Yunbing Hou, Zhaoxiang Zhang, Haifeng Duan, and Liming Xue School of Resources and Safety Engineering, China University of Mining & Technology (Beijing), Beijing 100083, China (Received 2006-02-03)
Abstract: Based on the externality theory and the environmental value theory, the hypothesis of charging for waste dumping of open-pit metal mines was put forth. The charging methods were designed according to the characteristics of waste dumping of openpit metal mines, including charging based on the dumping amount of the total waste, multi-charging factors, exceeding standard punishment charging, and so on. The main charging parameter is based on the dumping area rather than the total amount of waste dumping. The charging model of waste dumping of open-pit mines was formulated, and the charging rate was divided into two parts, i.e., the standard charging rate and the differential charging rate. The standard charging rate was derived using the equilibrium dynamic model, whereas the differential one was obtained by establishing the fuzzy synthesized evaluation model,
Key words: open-pit metal mine; waste dumping; charging pattern; basic charging rate; differential charging rate
1. Introduction
and the reclamation percentage has reached 92% [5-61.
The problem with regard to the extent of the area occupied by waste dumping has been receiving considerable attention in recent years. The total area occupied by mining has reached approximately 5 8 6 ~ 1 0m2 ~ and the destroyed area is 1 5 7 ~ 1 m2, 0 ~ an annual increase by 4x108 m2 [l-41. Mined ore or product from open-pit mines is approximately 30% of the total amount in China. The average destroyed land area is about 7x 106-1OOx lo6 m2 per year, and the accumulated stripped waste of open-pit mines has reached 11.0x109 t. Hence, the total destroyed area is 1 6 7 8 2 ~ 1 m2 0 ~ from 1949 to 2001, and on an average, the height of the dumped waste dump is 22 m.
The hypothesis of charging for waste dumping of the open-pit metal mine is put forth, and the calculation model of charging rate is formulated in this article, considering the special mine environment and referring to the measures taken by the countries all over the world [7].
In USA, waste dumping is regulated by a strict environmental control resources exploitation strategy rather than an “efficient pollution level” put forth by Pigou. As a nation that abounds in mineral resources, Australia considers land reclamation as a precondition to allow the right to exploit mines and establishes the principle of prevention first according to “National Ecological Sustainable Strategy” issued by the government. Germany pays much attention to mine environmental prevention, particularly to open-pit mines, and some local governments prohibit open-pit mine exploitation through legislation. The waste dumping is temporarily restricted to the outside of the stope, and later the mining pit should be filled and leveled up by discarding rocks. The land of the mine must be restored Corresponding author: Yunbing Hou, E-mail: houyunbing20W@ 163.~0111
2. Objective It is impossible to totally regain the past physiognomy and land utility after mine exploitation has been completed. Restoring all of the occupied and destroyed land can and should be done, which is a primary objective with respect to environmental protection. And the standard of quality of reclamation can be implemented according to soil environment quality standard. The objective of charging for mining waste dumping is to decrease the occupied land area by increasing the height of the dumped waste and to reduce the amount of waste dumping by reducing the production amount of the ores. The latter one rather than the elimination of waste dumping is the main function of the Pigou tax. Mining waste dumping has distinct characteristics compared with other pollutants, and the wastes that occupy the land are the main source of environmental pollution. The occupied area of the waste dumping is not only relevant to the amount but also to the height of the waste dumping. The occupied area of the waste dumping can either be increased or decreased by ra-
482
tionally adding or reducing the height of the waste dumping without charging its amount.
3. Charging pattern of the mining waste dumping The standard pattern of the charging for waste dumping is to ascertain the standard of the charging according to the expected function, charging gist, and controlled pollutant amount [8]. With respect to the charging function, there are mainly three charging patterns of waste dumping including stimulating, financing, and the mixed patterns; with respect to the charging gist, there are three patterns including charging according to the total amount, concentration, and medium; with respect to controlling pollutant and factors, there are three patterns including single factor, multi-factor and mixed patterns; there are five patterns including exceeding standard and within standard (concentration standard of the pollutant), exceeding and within permit (license with respect to the extent of pollution), and exceeding both standard and permit patterns if classified by the relationship between the pollution charging standard and environment standard. A total of 135 charging patterns can be obtained by permutation and combination of the patterns listed above [8]. The objective of the charging for waste dumping of the open-pit mine is to promote mine corporations to occupy less land and try to implement land reclamation earlier and ultimately restore natural environment. Therefore, when the method and standard of the charging for waste dumping is established, the fact that whether it can have a good stimulation function to the enterprises must be considered. Furthermore, in establishing the charging patterns, the financial function must be considered because financial shortage is the main cause of the low percentage of land reclamation rate. Therefore, the stimulation of decreasing pollution and finance are the basic principles for establishing the policy of charging for waste dumping.
J. Univ. Sci. Technol. Beijing, Vobl3,N0.6, Dec 2006
waste dumping has no unique standard. Charging according to the amount of waste dumping is unequal and disadvantageous to control pollution. This charging pattern is only a financial means and can neither serve as an incentive to improve the environment nor achieve the aim of improving the environment. Charging based on the total amount of the waste dumping by mining can be accepted easily by mines. However, it cannot stimulate mining corporations to reduce their pollution. According to the externality theory, to maximize their profit, mine corporations will control the production and waste dumping within an effective level when pollution tax is based on the total waste dumping. Therefore, charging for waste dumping can reduce ores or waste dumping. The decrease in the amount relies on the fluctuation of the demand of the ores in the market. If a kind of medium that is not only closely related to the amount of the waste dumping but can directly influence the objective of pollution control or reduction can be found, then charging based on this medium can be feasible. In fact, the waste dump occupies and destroys land and changes the natural scenario of the land, thus bringing out maximum damage. The objective of controlling or reducing the amount of the waste dumping caused by mining is achieved through controlling the extent of the area of the occupied land, while simultaneously controlling the time of occupancy. The ultimate objective of charging for waste dumping is to reduce the extent of land occupied by waste land and to facilitate earlier restoration of land. Accordingly, considering the extent of occupied land and the length of occupied time as the medium of charging is feasible and effective.
Charging according to “concentration” can be understood as the difference in heavy metal content and radioactivity intensity of the mining waste dumping.
With respect to controlling pollutant and factors, there are three charging patterns including single factor, multi-factor, and mixed patterns. Besides occupying the land, the waste that is dumped from mining can also bring about pollution such as heavy metal, radioactivity, and powder diffusion. Therefore, when the charging method is established, many factors should be fully considered.
In the past, the ore production amount was the main factor in the tax and charging such as resource tax, resource compensation charging, and the environment ecology compensation charging. However, the area occupied by mining waste dumping cannot be directly calculated by the production amount of ores because the large difference between ores distributing condition and the discrepancy of stripping-to-ore ratio can range from 2 to 15, and the other reason is that the height of
To implement the charging exceeding standard or permit, the first step is to determine all kinds of environmental standard. Constructing a standard amount of the waste dumping is impossible owing to the limit of the stripping-to-ore ratio. The feasible method is to determine a height standard (or discharging ores inside the stope) to reduce the occupied area, and to restore the land ahead of schedule, thereby shortening the length of the occupied time. Therefore, the standard is
Y.B. Hou et aL, Charging for the waste dumping of open-pit metal mines
483
still the area and length of time. Moreover, a comprehensive standard can be established and the charging for extra waste dumping will be imposed when the dumping exceeds the standard that is established.
mation fare of unit area is u , the forest planting fare of unit area is v, if the amount of the charging can just compensate the reclamation and forest planting fare, there is
4. Determination of the charging rate of waste dumping
c =(u+v)s
The charging rate is the primary step in the implementation of the charging for waste dumping.
4.1. General calculation model of the charging rate of waste dumping The objective of charging for waste dumping is to internalize all of the exterior damage resulting from the occupied land of waste dumping. To identify the purpose of charging and achieve the final objective with regard to environment protection, the charging rate of waste dumping can be divided into two parts: (1) the basic charging rate and (2) the differential charging rate. The charging imposed according to the basic charging rate is mainly used to reclaim the destroyed land and plant trees. So this reclamation should be introduced into the occupied area. The charging imposed according to the differential charging rate is mainly used to compensate for the pollution resulting from powder, carbon loss, radioactivity, and heavy metal, and because such pollution is proportional to the area occupied, the differential charging rate should be based on the basic charging rate and the former should be modified as a coefficient. The differential charging rate should be determined by the method of fuzzy evaluation based on the degree of environmental destruction. The total charging rate can be obtained by
P =P 1+P2
(1)
where p is the total charging rate, Wm2; p , the basic charging rate, Wm2;andp, the differential charging rate, Wm2.
4.2. The basic charging rate of waste dumping Suppose there is a mine where the basic charging of waste dumping is c, the area it occupied is s, the recla-
(2)
where c is the basic charging rate of waste dumping, Y ; s the area occupied by waste dumping, m2; u the reclamation fare of unit area, Wm2;v the forest planting fare of unit area, U/m2. The reclamation and forest planting fare can be obtained by financial budget. Hypothetically there are k working procedures in reclamation land and there are 1 working procedures in forest planting. u and v can be calculated by the following formula: 1
k
u=-&,
v=cvj
i=l
(3)
j=1
where u, is the fare of unit area of reclamation procedure i, Wm2; vi the fare of unit area of forest planting procedure j , Wm2. Then we have I
k p1
(4)
=u+v=cu;+cvj i=l
j=1
Eq. (4) is a static model without considering inflation and consistent with the tax and charging policy implemented by the nation. Such charging policy will result in the charging rate of waste dumping lower after a while. To solve such problem the dynamic equilibrium model and standard optimum model will be better. Suppose the service life of a mine is n, the inflation rate is 9, Eq.(4) can be modified to
[
I
p1 =(l+p)"-'X u ; + c v j j=1
)
(5)
If the time value of money is considered, because the area occupied is different from one year to another, there is
[i + c 'i I
(1 + p),-l
PI =
vj s
ui
(i=l
j=1
),
(1+p)"-1s1+(1+p)"-2s2+...+(l+p)"-'s, +...+ s,
where p is the bank interest rate; s, the area occupied in the year t , m2. Eq. (6) is the dynamic charging rate of reclamation in the year during which the exploitation is completed. PI is not only related to the cost of land reclamation and forest planting but also to the service life of mines, the inflation rate in a certain period, the bank
interest rate, and area occupied annually. The dynamic charging rate is related to the area occupied annually and the statistical area can only be obtained after the exploitation is completed. This problem can be transformed into another one: assume that the area occupied is equal from one year to another, that is
J. Univ. Sci. Technol. Beging, voLz3, N0.6,Dec 2006
484
spective patterns. Suppose the synthesized evaluation coefficient of mine i is bi ( O I b i 51, i = l , 2 ; . . , m ) ,
sI=sz=s3=*--=s,,then there is
P1=
(1 + p y - l
+ (1+ g 2 +. ..+ (1+gr + +1
(7)
and if the basic charging rate is pl, then the differential charging rate of mine i is
** *
4.3. The differential charging rate of waste dumping (1) The synthesized index system of charging for waste dumping.
After the analysis of all kinds of factors that influence the charging rate base of waste dumping, the indices can be classified into three categories as economic, environmental, and geological mining index:
1) Economic index, which comprises: production scale, total mine investment, unit mineral ore price, unit mineral ore exploitation cost, unit rock exfoliation cost, and return on investment. 2) Environmental index, which comprises: CaF content, pollution caused by radioactivity, pollution caused by heavy metal, pollution caused by silicon in mineral powder, carbon content of occupied land, sulfur and phosphor contents, and other pollution. 3 ) Geologic and mining technology index, which comprises: quality of minerals, rock-discharging mode, exfoliation ratio, smelting quality, exploitation quality, geological reserve, and quality of processing.
(2) Formulating the synthesized valuation model.
PZi
=
0.4 I bi < 0.6
(9)
( 3 ) Application of the differential charging rate model. Appendix 1 is the statistics of the mines evaluated. Appendix 2 is the results of the differential charging rate of the mines. The result shows that the differential rate can reveal the specific conditions of the mines because the economical, environmental, and geological mining conditions are all considered. The stripping rate of Western mine has reached 10 t/t and it causes radioactivity and fluorine pollution; therefore, its toll is comparatively high; Baiyun ebo metal mine also causes radioactivity pollution, but it applies belt transportation so the charging rate is in a middle level.
5. Conclusion
matrix; R denotes the fuzzy relation called evaluation index subjection degree matrix; B is the synthesized
A large amount of land is occupied by waste dumped out of open-pit metal mines, which results in damage to the environment and people residing in areas close to the mines. If the policy of charging for waste dumping can be implemented, the problem financing for land reclamation can be solved and the mines can be stimulated to increase the height of waste dumping and to take measures to reclaim land ahead of schedule, thereby reducing the expense on waste dumping and protecting the natural environment. The policy of charging for waste dumping can also promote such green waste dumping pattern as dumping inside pit and using belt transportation. The application of green waste dumping style can bring about a novel innovation of techniques of waste dumping of open-pit metal mines.
evaluation result matrix; and bi denotes the evaluation result of mine i.
References
Hypothetically, if there are m evaluation mines and n evaluation indices, then there is a fuzzy evaluation relation between evaluation events and evaluation indices:
n
where Olaill, X u i = 1; A is the weight coefficient i=l
( 3 ) Determining the differential charging rate. The differential charging rate can be determined by the fuzzy synthesized evaluation. Different open-pit mines can be divided into different charging patterns. The differential charging can be imposed by their re-
[ 11 China Mining Association, China Mining Statistical Year-
book 2002 (in Chinese), Geological Press, Beijing, 2002. p.365. [2] Q.Y. Li, Influences of mineral resource exploitation on environmental quality in China (in Chinese), China Min., 11(2002), No.2, p.47.
Y.B. Hou et al., Charging for the waste dumping of open-pit metal mines [3] H.L. Shi, Review of the research of the ecological environmental protection in mining districts (in Chinese), Met. Mine, 2000, No.9, p.41. [4] F. Zhao, Sudy on the development of China's mineral resources and pollution control (in Chinese), China Min., 12(2003),No.6, p.8. [5] D. Pearce and R. Turner, Economics of Natural Resources and the Environment, Harvester Wheatsheaf,London, 1990, p.12.
485
[6] OECD, Managing the Environment: The Role of Economic Instrument, OECD, Paris, 1994, p.36. [7] H.F. Duan, Study on the Pollution Charge on the Waste Rock in Strip Iron Mine and Impact to the Exploitation [Dissertation] (in Chinese), China University of Mining & Technology, Beijing, 2004, p.26. [8] J.T. Yang, The Reform and Design of Pollution Chargings System in China, China Environmental Science Publishing House, Beijing, 1998, p.120.
Appendix 1. Statistics of the mines evaluated Mines evaluated Name of evaluation index
Economic indices
Baiyun
Heinao-
Gongyi-
Sanhe-
Huang-
ebo
bao
ming
ming
gang
Production scale / lo5 t
loo0
150
200
400
500
Total investment amount /Y 10'
16
2.8
3.2
2.2
Unit mineral ore price / @.t-')
100
140
130
43
78
85
Unit mineral ore exploitation cost I (u t-1)
Environmental
Damao
Damao
west
north
50
800
300
6.5
1.2
14
5.2
110
145
135
95
90
67
48
54
67
58
Guying
Unit rock exfoliation cost I ( u d )
5.8
4.2
3.8
5.5
4.3
6.2
4.8
5
Total occupied area / l@ m2
1568
420
220
340
458
120
4790
340
CaF content
more
less
less
less
medium
medium
more
more
Pollution of radioactivity
more
less
less
less
less
less
more
medium
Pollution of heavy metal
less
less
less
less
less
medium
more
medium
medium
medium
medium
more
more
less
more
more
Carbon content of occupied land
less
medium
medium
medium
more
medium
less
less
Sulphur and phosphor content
more
less
less
medium
medium
more
more
more
Pollution of silicon in mineral
indices
Geologic and mining
Other pollution
medium
medium
less
less
medium
less
more
more
Quality of minerals / %
45
50
41
35
37
43
34
37
Transportation style
railway
truck
truck
truck
railway
truck
Exfoliation ratio / (t.t-')
2.6
1.5
2.2
3.2
2.3
1.1
Smelting quality of minerals
bad
excellent
good
good
good
good
bad
bad
Quality of exploitation
easy
difficult
medium
medium
medium
medium
difficult
difficult
Geological reserve / lo8t
3
0.5
0.8
1.2
0.6
0.5
8
0.5
Quality of processing I %
32
36
34
35
33
35
32
33
technology indices
adhesive tape 10.5
truck 6
Appendix 2. Results of the differential charging rate of the mines Mine Charging
Baiyun ebo
Heinaobao
Gongyiming
Sanheming
Huanggang
Guying
1.000
0.5798
0.5783
0.5925
0.6104
0.607 1
Damao
Damao
west
north
2.1343
2.01 1