Tilling/Mining may disturb the ground compaction... If the ground compaction is disturbed, the blending of top soil , sub soil and regolith may occur. As the result... denitrified infertile soil may be formed... since fertility is indirectly proportional to the soil compaction

In addition, generally mining dust changes the texture of parents soil as well as add contamination like metals (have metals as well as transition metals). And if these metals are in bio-available fraction, plants uptake which causes accumulation of toxic metals in plants.

Further, if the mining practices are not well controlled, the wash off from the over-burden dumps (containing toxic metals) may find ways into the nearby lands and that may reduce the fertility of soil.

Actually, all the listed opinion are in line. But i want to emphasize at this juncture that the main cause of the infertility of mining areas is the total removal of cover plants. In the cause of mining, these cover plants that add litter and protect the soil are removed, then degradation is enhance through the process of removing soil to unearth the ores.

Obviously, the total removal of plants, also causes more wreathing (physical as well as chemical) to the soil and increases surface runoff. which leads to decrease in soil nutrients and soil organic matter.

Acid mine drainage is the most common and most immediate impact of mining activities. run-off from mines into surrounding environments alter the pH of the receiving soil significantly and ultimately its fertility.

In my opinion soil (a minor mineral) mining impacts soil fertility as it involves the complete removal of top fertile soil. If the top soil is infertile no question would arise of any environmental damage. Furthermore the likely impacts of soil mining depend largely upon the mine-able area, mine-able reserve and ecology of existing surroundings. The bio-chemical structure of infertile, non-arable and non-forested soil (or whatever case may be) provide sufficient ground to predict the impacts.

I recommend to consider

1) Change in Natural drainage (if mining area leis near a water body).

2) alteration of bio-physico-chemical characteristics of leftover soil patches.

3) the depth of soil excavation

4) fate of pits after closure of mine.

Moreover; mining it self is environmentally unsafe. If mining has already been started it is worthless to ask for environmental well being.