The Anatomy of a Mine - Mining and the Environment: From Ore to Metal - page 184

parameters to support mine planning and evaluation of the economic viability of the
deposit. The estimate is based on detailed and reliable exploration and testing information
gathered through appropriate techniques from locations such as outcrops, trenches, pits,
workings, and drill holes that are spaced closely enough for geological and grade continu-
ity to be reasonably assumed.
Measured Mineral Resource is that part of a Mineral Resource for which quantity, grade
or quality, densities, shape, and physical characteristics are well established ( Case 4.3 ).

Mineral Reserve
Mineral Reserve (also termed Mineable Reserve) is the economically mineable part of a
Measured or Indicated Mineral Resource demonstrated by at least a preliminary feasibility
study. This study must include adequate information on mining, processing, metallurgical,
economic, and other relevant factors that demonstrate, at the time of reporting, that eco-
nomic extraction can be justii ed. A Mineral Reserve allows for dilution of ore by nearby
non-ore materials and allowances for losses that may occur when the material is mined
and processed, including unrecovered mineral that will be included in the tailings.
Statistical studies have shown that less than 5 percent of the total number of a specii c
type of mineral deposit produce more than 90 percent of that commodity or group of
related commodities (McLemore 2005). These deposits, so-called 'world-class' deposits, are
the largest of the known deposits in the world in terms of size and grade.
Probable Mineral Reserve is the economically mineable part of an Indicated, and in some
circumstances a Measured Mineral Resource, demonstrated by at least a preliminary feasibil-
ity study. This study must include adequate information on mining, processing, metallur-
gical, economic, and other relevant factors that demonstrate, at the time of reporting, that
economic extraction can be justii ed. Proven Mineral Reserve is the economically mine-
able part of a Measured Mineral Resource demonstrated by at least a preliminary feasibility
study. This study must include adequate information on mining, processing, metallurgical,
economic, and other relevant factors that demonstrate, at the time of reporting, that eco-
nomic extraction is justii ed.

Less than 5 percent of the
total number of a specifi c type
of mineral deposit produces
more than 90 percent of that
commodity or group of related
commodities.

CASE 4.3
Watch Out for Salting

This old and dishonourable method of making a min-
ing prospect seem better than it is, has unfortunately
not vanished. While as old as mining itself, the most
recent and probably most remembered 'salting' case is
the Bre-X case. In 1996. Bre-X, a little known Canadian
mining company, convinced fi nancial markets, as well as
the then President Soeharto in Indonesia of the discov-
ery of a gold resource in East Kalimantan, with a value
well in excess of several tens of billion US dollars. Only
subsequent independent third party drilling suggested
salting, whereby rich ore or native gold is mixed before
(or even after) it has reached the assayer. The bonanza
mine turned into a hoax with the loss of hundreds of
millions of US dollars for the unfortunate shareholders,
not to mention the embarrassment for the Indonesian

Government. Salting can be achieved by adding metallic
gold in the material to be sampled or the sample itself.
Not all salting, however, is due to dishonesty; careless-

ness in sample preparation or in the laboratory may
result in accidental salting.