Environmental Engineering Reference
In-Depth Information
continue and the general degree of knowledge of the actual mineral accumulation and
its geological environment increases. Advanced computerized resource modelling will
further inl uence the dei nition of the deposit.
●
Economic limits differentiate between mineral accumulation and ore. Economic con-
cepts are used to dei ne zones of rich ore(s) and zones of lean ore(s) within the deposit
calculated on a balance between general production costs and net income, including
proi t margin. Market l uctuations could lead to the consideration in turn of one part
or another of the mineralization as a rich ore, or as a lean ore, or as mining waste.
●
Technological limits are concerned with the optimal conditions for mining the ore.
Depending on a number of morphological criteria (depth, dissemination, or segrega-
tion in a formation or datum level, dip, type of substance), the pre-feasibility study
makes an initial recommendation on the mining method designed for optimal recov-
ery in terms of quality and cost from the many mining methods available for surface
or underground workings. For the miner, only the part of the ore accessible by the
available mining techniques actually dei nes the deposit.
●
Environmental limits recognize the importance of safeguarding the mine environment.
Miners, during the early years of commercial mining, wanted only one thing: valuable
minerals. They didn't care about elegance, craft, aesthetics, or the environment. In most
cases in these days before environmental consciousness, they developed a mineral deposit
without considering the long-term environmental consequences. Today's mine devel-
opments differ. They are, from the outset, subject to intense scrutiny from the public,
including anti-mining advocacies. Environmental concerns are addressed and accommo-
dated, and may even prevent a mine from being developed. On the other hand, share-
holders and their Board representatives may demand that the NPV be maximized.
Showstoppers are manifold: mineral deposits may be located in or near protected areas;
endangered species may be present in the mining areas; there may be a lack of safe on-land
tailings disposal sites; traditional land ownership issues may be unresolved; mine develop-
ment would result in signii cant resettlement; or widespread community opposition etc.
Miners, during the early years of
commercial mining, didn't care
about elegance, craft, aesthetics,
or the environment.
●
Political limits are a rel ection of the large capital investment that a new mine devel-
opment commands. Is the host jurisdiction stable and investor friendly? Are there
security concerns? The overall political instability of some countries can be a great
deterrent to the development of mines. Mining companies working in many develop-
ing countries can also encounter problems such as high tax and tariff costs, and the
corruption of civil servants such as customs ofi cials, without whose help they would
have difi culty implementing their project. A favourable, stable investment climate is
required to attract the amount of money required to develop a mine. Country risk also
inl uences interest rates charged by the international i nancial markets. Higher coun-
try risk premiums may cause a mine investor to allocate funds to countries with lower
risk rating. Somewhat perversely, however, the existence of any combination of nega-
tive factors leads to less exploration in that country or region, which, for a more adven-
turous company, can increase the chances of discovering a large ore body.
A favourable, stable investment
climate is required to attract the
amount of money required to
develop a mine.
Preparing the Bankable Feasibility Stage
A feasibility study represents the last and most detailed step for evaluating a mining project
for a 'go/no-go' decision and i nancing purposes. The principal parameters for a feasibil-
ity study (FS) are based on sound and complete engineering and test work. Accuracy is
higher than the pre-feasibility study and is typically around 10 to 15 percent. Feasibility
study objectives are the same as for the pre-feasibility study, but the level of detail and
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