Is cyanide dangerous?

Written by Catalin Hosu

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Gold is leached from rock (ore) by using cyanide in a closed processing system.

Cyanide occurs naturally in the environment and is used every day to make common products for our use.  Its use is normal – 90% of gold mining operations worldwide utilise cyanide and it is used to make jewellery, glue, electronics, fireproof insulation, cosmetics, nylon, medicines, table salt, winter road salt and other products used in our daily lives.

It can be poisonous in high concentration and if used unsafely – like many everyday substances including household bleach.

Like any chemical it must be used with care – we would use a ‘closed circuit’ cyanide leaching system and our standards in dealing with waste water are twice as high as EU regulations require, which in turn are 5 times more stringent than US and Australian regulations.

As a result clean water would replace existing polluted waters of the Roşia Montană and Corna valley.  This in turn would allow aquatic life to return to Roşia Montană’s waterways during the operational phase of the mine.


Key facts:

  • Cyanide occurs naturally in the environment, in our food and in our bodies.
  • It is harmless unless we get a toxic dose all at once.
  • It cannot accumulate or build up in a system until it reaches a toxic level.
  • Large quantities of cyanide compounds are used every day to make common products for our use.
  • Cyanide in the environment is diluted and degraded into harmless substances by natural processes.
  • There are huge economic benefits for Romania that come with a healthy, productive mining industry. Closed circuit cyanide leaching is the only safe, environmentally-friendly and economical way the gold at Rosia Montana can be recovered.
  • The dangers inherent in the use of cyanide are real. But they are dealt with by industry all over the world.
  • When it comes to cyanide, unfortunately fear is often more marketable than knowledge.

The mining industry, and in particular the gold mining industry, has been using cyanide in its production processes for many decades. While cyanide is commonly perceived as being a deadly substance, it is in fact a widely used chemical that is essential to the modern world. The key to its safe use is the implementation of sound management practices.

While public concern about cyanide is valid and indeed understandable, much of the recent media attention and public reaction regarding the use of cyanide in mining operations has arisen due to a lack of understanding of the nature of cyanide and its effects on health and the environment.

Approximately 1.6 million tonnes of cyanide are manufactured worldwide and just 13 percent of the total amount is used in gold processing. Approximately 87 percent of the cyanide production is used in other industry sectors to manufacture other products used in our daily lives.

The use of cyanide in mining is actually the best practice around the globe, safe, proven, and highly regulated: cyanide technology is used safely in approximately 400 mineral processing plants worldwide including at the most modern gold mines in Europe, including in Finland and Sweden.

In addition, European Union legislation has created a strict legislative framework to ensure the safe use of cyanide and to ensure that dangers to human health and the environment are controlled. Any discharge containing cyanide in modern gold mines is treated in a cyanide destruction circuit, and consequently, the technology used today cannot be compared to prior practices e.g. used in Baia Mara until 2000.

Through a developed neutralisation process, the Roşia Montană mine would achieve a waste cyanide concentration significantly below the European Union mining standard of 10 ppm and even more significantly below the concentrations of 50 ppm often found in North American and Australian mining operations.

Additionally, the mining project has signed on to the International Cyanide Management Code, which was formulated by the United Nations and ensures independent inspection of the mining operation to guarantee compliance.

Here’s how the cyanide gold mining process works:

For more information, check out this fact sheet about gold mining using cyanide and its application in the Roşia Montană mining project.