Suitability Evaluation for Land Reclamation of Nonmetallic Mines in Xinjiang, China
Table 1
Evaluation indexes and grading of land reclamation for Xinjiang mines.
Limiting factors and analysis indexes
Grading of land reclaimed as farmland
Grading of land reclaimed as forest land
Grading of land reclaimed as grassland
Topological slope
<3
1
1
1
4∼7
2
1
1
8∼15
3
1
1
16∼25
4
2 or 1
2
26∼35
4
2
3
>35
4
3 or 2
4 or 3
Soil parent materials
Loam
1
Little influence
Little influence
Clay and sandy loam
2
Little influence
Little influence
Sandy soil
3
Little influence
Little influence
Sandy-gravel soil
4
4 or 3
Little influence
Thickness of cover soils (mm)
≥100
1
1
Little influence
99∼50
2
1
Little influence
49∼30
3
2 or 3
Little influence
29∼10
4
2 or 4
Little influence
<10
4
4
3or 4
Irrigation and drainage condition
Unsubmerged or occasionally submerged, with favorable irrigation and drainage
1
1
1
Seasonally submerged for a short time, with moderate irrigation and drainage
2
2
2
Seasonally submerged for a long time, with poor irrigation and drainage
3
3
3 or 4
Submerged for a long time, with almost no irrigation and drainage
4
4
4
Nonuniform settlement
No settlement
1
1
1
Mild settlement
2 or 3
1
2
Moderate settlement
4
2 or 3
3
Severe settlement
4
3
3
Degree of pollution
No pollution
1
1
1
Mild pollution
2 or 3
1
2
Moderate pollution
4
2
2
Severe pollution
4
3
3
Organic matter content in soil (%)
>10
1
1
1
10–6
2 or 3
1
1
<6
3 or 4
2 or 3
3 or 4
This table is derived from actual land reclamation carried out for mines in Xinjiang and the relevant national standards (completion standards on land reclamation quality). 1 denotes very suitable for land reclamation; 2 denotes somewhat suitable for land reclamation; 3 denotes not very suitable for land reclamation; and 4 denotes unsuitable for land reclamation.