Page 28 - Introduction to Mineral Exploration

1: ORE, MINERAL ECONOMICS, AND MINERAL EXPLORATION 11

sand and water from the UK to Saudi Arabia. minerals are adequate to meet the expected
Lower middle unit value minerals from cement demand for the foreseeable future, and so no
to salt can be moved over intermediate to long significant increases in real long-term prices
distances provided they are shipped in bulk are expected. Exceptions to this are likely to be
by low cost transport. Nearly all industrial sulfur, barite, talc, and pyrophyllite. Growth
minerals of higher unit value are internation- rates are expected to rise steadily, rates exceed-
ally tradeable, even when shipped in small lots. ing 4% p.a. are forecast for nine industrial
The cost to the consumer of minerals with minerals and 2–4% for 29 others. These figures
a low unit value will increase greatly with may well prove to be conservative estimates.
increasing distance to the place of use. Con- Contrary to metals, the recycling potential of
sequently, low unit value commodities are industrial minerals, with some exceptions, is
normally of little or no value unless available low, and competing substitutional materials
close to a market. Exceptions to this rule may are frequently less efficient (e.g. calcite for
arise in special circumstances such as the kaolinite as a cheaper paper filler) or more
south-eastern sector of England (including expensive.
London) where demand for aggregates cannot An industrial mineral, particularly one with
now be met from local resources. Considerable a low or middle unit value, should be selected
additional supplies now have to be brought as an exploration target only if there is an avail-
in by rail and road over distances in excess able or potential market for the product. The
of 150 km. For high unit value minerals like market should not be from the exploration area
industrial diamonds, sheet mica, and graphite, to keep transport costs at a sustainable level.
location is largely irrelevant.
Like metals, industrial minerals respond to
changes in the intensity of business activit- 1.3 IMPORTANT FACTORS IN THE ECONOMIC
ies, but as a group, to nothing like the extent RECOVERY OF MINERALS
shown by metals, and their prices are generally
much more stable. One reason for the greater
stability of many industrial mineral prices is 1.3.1 Principal steps in the exploration and
their use or partial use in consumer nondur- exploitation of mineral deposits
ables for which consumption remains com- The steps in the life cycle of a mineral deposit
paratively stable during recessions, e.g. potash, may be briefly summarized as follows:
phosphates, and sulfur for fertilizer production; 1 Mineral exploration: to discover a mineral
diatomite, fluorspar, iodine, kaolin, limestone, deposit.
salt, sulfur, talc, etc., used in chemicals, paint, 2 Feasibility study: to prove its commercial
paper, and rubber. The value of an industrial viability.
mineral depends largely on its end use and the 3 Mine development: establishment of the
amount of processing it has undergone. With entire infrastructure.
more precise specifications of chemical purity, 4 Mining: extraction of ore from the ground.
crystalline perfection, physical form, hardness, 5 Mineral processing: milling of the ore, sep-
etc., the price goes up. For this reason many aration of ore minerals from gangue material,
minerals have quite a price range, e.g. kaolin to separation of the ore minerals into concen-
be used as coating clay on paper is four times trates, e.g. copper concentrate; separation and
the price of kaolin for pottery manufacture. refinement of industrial mineral products.
Individual commodities show significant 6 Smelting: recovering metals from the min-
price variations related to supply and demand, eral concentrates.
e.g. potash over the last 40 years. When sup- 7 Refining: purifying the metal.
plies were plentiful, such as after the construc- 8 Marketing: shipping the product (or metal
tion of several large Canadian mines, prices concentrate if not smelted and refined at
were depressed, whereas when demand has the mine) to the buyer, e.g. custom smelter,
outstripped supply, prices have shot up. manufacturer.
According to Noetstaller (1988) already 9 Closure: before a mine has reached the end
discovered world reserves of most industrial of its life, there has to be a closure management