Journal of Resources and Ecology >
Evaluate the Reclamation Suitability of Dumps of Open-pit Coal Mines based on Niche Fitness in the Eastern Arid Desert Area in Northwest China
WEI Guangkuo, E-mail: 1249801439@qq.com |
Received date: 2022-11-11
Accepted date: 2023-03-05
Online published: 2023-07-14
Supported by
The Inner Mongolia Autonomous Region Science and Technology Major Project(2020ZD0021-03)
Suitability evaluation of land reclamation is an important prerequisite for determining the reuse of damaged land in mining areas. To make full use of land resources in mining areas and repair damaged land, this study takes four dumps in the eastern part of the arid desert area of northwest China as the research object, and uses the platform and slope as the evaluation unit to consider ecological land as the direction. The indicators affecting the reuse of dumps are selected as five aspects: Terrain conditions, soil conditions, location conditions, irrigation and drainage facilities, and environmental risks. The suitability evaluation index system of land reclamation based on niche fitness is constructed, and the obstacle degree is introduced to diagnose the obstacle factor. The results showed that (1) the niche fitness index of each unit in the study area was between 0.339 and 0.751, indicating that the suitability grade of reclamation for ecological land is typically low. The suitability index of the same dump platform (0.511-0.751) was generally higher than that of the slope (0.339-0.628). (2) Each factor responded differently to the obstacle degree of different units. The slope, gravel content, and drainage conditions are the key elements influencing the slope. The major obstacles for the platform are soil and drainage conditions. In soil conditions, the gravel content and bulk density of the soil are limiting factors of platform. The method developed here can be effectively used to evaluate the suitability of mining areas for reclamation. The results provide a scientific basis for the reclamation and ecological reconstruction of open-pit coal mine dumps in arid desert areas of northwest China.
Key words: niche fitness; dumps; land reclamation; suitability evaluation
WEI Guangkuo , LIU Jiaqi , ZHAO Tingning , YANG Jianying , LI Ruipeng , KUI Guoxian , AI Xianfeng , XIAO Fei . Evaluate the Reclamation Suitability of Dumps of Open-pit Coal Mines based on Niche Fitness in the Eastern Arid Desert Area in Northwest China[J]. Journal of Resources and Ecology, 2023 , 14(4) : 805 -815 . DOI: 10.5814/j.issn.1674-764x.2023.04.013
Fig. 1 Geographical location of the study area |
Table 1 Evaluation units of dumps in the study area |
Evaluation unit | MT platform | MT slope | LC platform | LC slope | TZ platform | TZ slope | XNY platform | XNY slope |
---|---|---|---|---|---|---|---|---|
Area (ha) | 22.98 | 122.01 | 23.74 | 78.63 | 46.75 | 68.88 | 3.2 | 49.11 |
Table 2 Classification and assignment of discrete indicators |
Index | Grade scale | Score |
---|---|---|
Irrigation condition | Satisfying irrigation | 100 |
Basic satisfaction | 80 | |
Irrigation difficulties | 50 | |
No irrigation facilities | 0 | |
Drainage condition | Guaranteed | 100 |
Unstable | 80 | |
Drainage difficulties | 40 | |
No drainage facilities | 10 | |
Peripheral land type | Farmland | 100 |
Grassland | 70 | |
Construction land | 50 | |
Bare ground | 10 | |
Heavy metal pollution degree | Pollution-free | 100 |
Slight pollution | 70 | |
Moderate pollution | 40 | |
Severe pollution | 10 | |
Geological disaster susceptibility | Unlikely | 100 |
More likely to occur | 60 | |
Easy to occur | 30 |
Table 3 Evaluation index system of ecological land suitability |
Criterium layer | Index layer | Optimum value | Minimum value | Maximum value | Type |
---|---|---|---|---|---|
Terrain condition | Slope (°) | 2 | 2 | 25 | Negative direction |
Soil condition | Soil bulk density (g cm-3) | 1.25 | 1.25 | 1.70 | Negative direction |
Gravel content (%) | 0 | 0 | 10 | Negative direction | |
Organic matter content (mg kg-1) | 20 | 5 | 20 | Positive direction | |
Soil layer thickness (cm) | 100 | 10 | 100 | Positive direction | |
Location condition | Peripheral land type | 100 | 10 | 100 | Positive direction |
Road distance (m) | 200 | 200 | 700 | Negative direction | |
Irrigation and drainage facilities | Irrigation condition | 100 | 0 | 100 | Positive direction |
Drainage condition | 100 | 10 | 100 | Positive direction | |
Environmental risks | Heavy metal pollution degree | 100 | 10 | 100 | Positive direction |
Geological disaster susceptibility | 100 | 30 | 100 | Positive direction |
Fig. 2 Single-factor niche fitness index diagramNote: Z1 to Z11 represent slope, soil thickness, bulk density, gravel content, organic matter content, surrounding land types, road distance, irrigation conditions, drainage conditions, heavy metal pollution degree and geological disaster susceptibility, respectively. |
Table 4 Weight of the reclamation suitability evaluation indices of the dump sites |
Index | Z1 | Z2 | Z3 | Z4 | Z5 | Z6 | Z7 | Z8 | Z9 | Z10 | Z11 |
---|---|---|---|---|---|---|---|---|---|---|---|
Entropy value | 0.71 | 0.77 | 0.78 | 0.76 | 0.73 | 0.58 | 0.74 | 0.66 | 0.66 | 0.29 | 0.75 |
Weight | 0.08 | 0.06 | 0.06 | 0.07 | 0.08 | 0.12 | 0.07 | 0.09 | 0.10 | 0.20 | 0.07 |
Table 5 Suitability grading of the different areas |
Grade | Suitability index | Implications |
---|---|---|
Highly suitable | >0.85 | Land use conditions are highly in line with the reclamation direction |
Moderately suitable | 0.75-0.85 | The land use conditions in the reclamation direction can be achieved with a little improvement. |
Barely suitable | 0.5-0.75 | Comprehensive renovation can achieve the land use conditions in the direction of reclamation. |
Unsuitable | ≤0.5 | Difficulties in ecological restoration and reconstruction |
Table 6 Comprehensive niche fitness index values of the different evaluation units |
Evaluation unit | MT platform | MT slope | LC platform | LC slope | TZ platform | TZ slope | XNY platform | XNY slope |
---|---|---|---|---|---|---|---|---|
Suitability index | 0.709 | 0.616 | 0.747 | 0.628 | 0.751 | 0.443 | 0.511 | 0.339 |
Appropriate grade | Barely suitable | Barely suitable | Barely suitable | Barely suitable | Moderately suitable | Unsuitable | Barely suitable | Unsuitable |
Fig. 3 Obstacle degree diagram of the evaluation units |
Table 7 Obstacle degrees of the main obstacle factors in each dump unit |
Evaluation unit | Factor ranking | Cumulative obstacle degree | ||
---|---|---|---|---|
1 | 2 | 3 | ||
MT platform | C4 (0.21) | C10 (0.20) | C2 (0.16) | 0.57 |
LC platform | C4 (0.23) | C2 (0.19) | C3 (0.18) | 0.60 |
TZ platform | C6 (0.24) | C9 (0.19) | C2 (0.15) | 0.62 |
XNY platform | C9 (0.18) | C7 (0.15) | C4 (0.14) | 0.46 |
MT slope | C1 (0.21) | C4 (0.17) | C10 (0.16) | 0.54 |
LC slope | C1 (0.22) | C10 (0.16) | C4 (0.14) | 0.52 |
TZ slope | C9 (0.16) | C1 (0.14) | C4 (0.12) | 0.42 |
XNY slope | C9 (0.13) | C1 (0.12) | C4 (0.11) | 0.36 |
Table 8 Difficulty grades of obstacle factor transformation |
Degree of transformation | Obstacle factor |
---|---|
Difficult | Slope, gravel content, surrounding land types, road distance, heavy metal pollution degree, geological disaster susceptibility |
Easy | Soil bulk density, soil thickness, organic matter content, irrigation conditions, and drainage conditions |
[1] |
|
[2] |
|
[3] |
|
[4] |
|
[5] |
|
[6] |
|
[7] |
|
[8] |
|
[9] |
|
[10] |
|
[11] |
|
[12] |
|
[13] |
|
[14] |
|
[15] |
|
[16] |
|
[17] |
|
[18] |
|
[19] |
|
[20] |
|
[21] |
|
[22] |
|
[23] |
|
[24] |
|
[25] |
|
[26] |
|
[27] |
|
[28] |
|
[29] |
|
[30] |
|
[31] |
|
[32] |
|
[33] |
|
[34] |
|
[35] |
|
[36] |
|
[37] |
|
[38] |
|
[39] |
|
[40] |
|
[41] |
|
[42] |
|
[43] |
|
/
〈 |
|
〉 |