Mining for Closure: Policies, practises and guidelines for sustainable mining and closure of mines

operations, re-vegetation of abandoned or filled mine waste areas including tailings impound- ment areas; removal and/or disposal of any obsolete structures and materials as per a final rehabilitation and closure plan; backfilling of approved underground or surface excavations using mill tailings to reduce tailings impound- ment areas; methods to reduce or eliminate soil erosion and stabilization of the site which will facilitate re-vegetation and reclamation; placement of waste rock in the underground workings or open pits, or by covering the waste rock with till or topsoil and then re-vegetating in an acceptable manner, and so forth. Mining legacy – (orphaned mines) abandoned mining operations or facilities for which a re- sponsible party no longer exists or cannot be lo- cated. The term mining legacies can often refer to a very much older site, where minerals op- erations have ceased decades, or even centuries ago. For reasons of its generality in the litera- ture, this term is used loosely in this report. 12

operations, such sites are frequently referred to as being under care and maintenance. Abandoned mine site – an area formerly used for mining operations (an idle/inactive site) that is neglected and whose legal owners still exist and can be located. Orphaned mine site – abandoned mining op- erations or facilities for which the responsible party no longer exists or cannot be located. Mine Decommissioning – the process that be- gins near, or at, the cessation of mineral pro- duction. This term is often used interchange- ably with Mine Closure but here refers to a transition period and activities between cessa- tion of operations and final closure. 11 Rehabilitation (Reclamation) – the return of the disturbed land to a stable, productive and/or self- sustaining condition, taking into account bene- ficial uses of the site and surrounding land. Progressive Rehabilitation – A process refer- ring to the ongoing rehabilitation of mine sites and mineral related facilities during the opera- tional life of a facility. Progressive rehabilitation may include works such as re-vegetation of ar- eas disturbed during project development and 11. The concept of mine closure is an issue by itself. However, an in-depth analysis is not within the scope of this report. For a more complete analysis of the concept of mine closure see Mudder, Ter- ry and Kevin Harvey, Closure Concepts. Mineral Resources forum, UNEP, 1999. “There are many different words used to describe closure including decommissioning, reclamation, rehabilitation, and post-closure. In this paper, decommissioning is referred to as the transitional period between cessation of operations and final closure. Reclamation refers to the physical aspects of earth mov- ing, regarding and revegetation. Rehabilitation is another word for closure used primarily in countries other than the United States. Closure is a term reserved for the point in time at which revegeta- tion has been completed, excess solutions have been eliminated to the extent practical, the maximum degree of passive management has been implemented, and a final surface and/or ground water monitoring programme has been initiated.” 12. In many instances throughout the literature, the term “legacy site” is used somewhat interchangeable with “orphan site” and even with “abandoned site”. Universally, its usage is also applied in the general sense (such as “legacies of the past” and “legacies of mining”). In the Caldata report cited above, “legacy” has been rede- fined as an equivalent to “abandoned” for this report. For reasons of the general application of the word “legacy”, that definition will be avoided. In essence within this discussion, a legacy site is an or- phan site, but the term can also encompass a site where regulatory obligations (if they ever existed) for site reclamation were fulfilled at the time of activity cessation (and thus where the tenement has been relinquished and liability – if it ever existed – extinguished) but where whatever reclamation performed was insufficient to render the site “closed” as termed in this document (and as devel- oped throughout this document). 13. Question marks (?) in this diagram indicate that the actual path- way to be followed is unknown, or can be influenced. • • • • •

•

Mine site

Active

?

Idle/inactive

?

Care & maintenance

Neglected

Abandoned

Orphan/Legacy

?

?

Closed

?

Figure 1.1 Mineral site status diagram for this docu- ment 13

Another very important term and concept utilised in this document is “best practice environmental management in mining” . In general, the usage of this term (and the shorter term “best environmental practice mining” ) is intended to capture the man- agement ethos portrayed in a series of more than twenty booklets published by the Australian Gov- ernment’s Department of Environment and Herit- age. Each booklet seeks to describe best practice for a particular key aspect of environmental (and in- deed, social) management as applied by Australia’s

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MINING FOR CLOSURE