Land recultivation? Land revegetation? Land reclamation? Land rehabilitation?
Reclamation can be used in this context, but I think in this situation the most appropriate word would be "remediation", from the Latin word remediare which means "heal" or "cure". It is most often used in the sense of fixing environmental problems such as pollution or contaminants.

https://en.wikipedia.org/wiki/Environmental_remediation

A Google search suggests this is a widely used term in the mining industry for the situation you describe.
https://www.google.co.uk/search?q=remediation+mining

It does depend exactly which stages you're attempting to describe, though. From http://www.miningfacts.org/environment/what-happens-to-mine-sites-after-a-mine-is-closed/:


  The terms reclamation, remediation, rehabilitation, and restoration
  are all used to describe mine closure activities that attempt to alter
  the biological and physical state of a site. [11] The terms are
  sometimes used interchangeably, and are closely linked, but refer to
  distinct steps in the preparation of the site for another use: [11,
  12]
  
  Remediation: The cleanup of the contaminated area to safe levels by removing or isolating contaminants. At mine sites, remediation
  often consists of isolating contaminated material in pre-existing
  tailings storage facilities, capping tailings and waste rock piles
  with clean topsoil, and collecting and treating any contaminated mine
  water if necessary.
  
  Reclamation: The physical stabilization of the terrain (dams, waste rock piles), landscaping, restoring topsoil, and the return of
  the land to a useful purpose.
  
  Restoration: The process of rebuilding the ecosystem that existed at the mine site (where applicable) before it was disturbed. The
  science of mine reclamation has evolved from simple revegetation
  activities to a discipline which involves using native plants to mimic
  natural ecosystem development over an extended period of time. [13]
  
  Rehabilitation: The establishment of a stable and self-sustaining ecosystem, but not necessarily the one that existed before mining
  began. In many cases, complete restoration may be impossible, but
  successful remediation, reclamation, and rehabilitation can result in
  the timely establishment of a functional ecosystem.


See also this publication by USGS:
Finger, Church, and Guerard. Potential for Successful Ecological Remediation, Restoration, and Monitoring, Integrated Investigations of Environmental Effects of Historical Mining in the Animas River Watershed, San Juan County, Colorado, 2008; U.S. Geological Survey Professional Paper .