Converting Minerals to Metals - Mining and the Environment: From Ore to Metal - page 272

human fatalities. Other relevant facts that help to put the toxicity of cyanide into context
include:
●

There are well-established threshold concentrations, below which cyanide expo-
sure is completely harmless. (This is in contrast to some toxins which can be
cumulative, or others which are considered to pose risks at even extremely low
concentrations);

●

Forms of cyanide occur in nature, particularly in many plants and their fruits, and are
commonly consumed in small amounts without adverse effects;

●

Cigarette smoke contains cyanide at concentrations above those that would be permit-
ted in a working environment;

●

Toxic forms of cyanide tend to be reactive and unstable and hence are subject to natural
degradation by a variety of reactions, and generally do not persist in the environment.

Residual cyanide after gold adsorption occurs as free cyanide (CN ) plus a variety of metal
cyanide complexes of differing toxicities, some of which are weak and readily dissociated.
Table 6.4 lists the cyanide species found in gold mine tailings with information on stability
and toxicity.
There remains a need for wider public education, information, and communication,
but what counts most is overall industry performance, since the public judges the industry
by its worst performers, not its best. Recent accidental cyanide tailings and effluent spills
have tended to affect public confidence in the mining sector (see also Chapter Eighteen).
In January 2000, the accidental release of large amounts of cyanide effluent from the
Aurul mine in Romania resulted in major media exposure of the cyanide leaching process
and the resulting river pollution (see also Case 18.3). In March 2000, a second accident at
another nearby mine released heavy metal-containing effluent and sludge into the same
river system. These unfortunate spills tend to mask the overwhelming safe performance of
hundreds of mines over many decades.
The Cyanide Code has been developed as a joint initiative between groups of gold
mining companies and cyanide producers, with the objective of encouraging and facili-
tating the responsible management of cyanide. It is a voluntary code for producers,
transporters and users of cyanide, with specific verification protocols for each of these
groups. The Code contains a series of nine Principles, each of which is supported by
one or more Standards of Practice, as shown in Table 6.5 . The Code is administered by the
International Cyanide Management Institute, a non-profit, industry sponsored corpora-
tion whose responsibilities are to:
●

The Cyanide Code has been
developed as a joint initiative
between groups of gold
mining companies and cyanide
producers, with the objective
of encouraging and facilitating
the responsible management of
cyanide.

Promote adoption of and compliance with the Code, and to monitor its effectiveness
and implementation within the world gold mining industry;

●

Develop funding sources and support for Institute activities;

●

Work with governments, NGOs, financial interests and others to foster widespread
adoption and support of the Code;

●

Identify technical or administrative problems or deficiencies that may exist with Code
implementation; and

●

Determine when and how the Code should be revised and updated.

Signatories must submit the relevant operations to rigorous certification and verification
procedures including an external audit every three years. Transparency is assured through
publication of Summary Audit Reports and Action Plans on the Cyanide Code website
( www.cyanidecode.org ). The Code was first introduced in 2005, and by the end of 2006,
had 27 signatories throughout the world including 14 mining companies, 8 cyanide pro-
ducers and 5 cyanide transporters.