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Water of Roșia Montană

Documents:  Water Management and Erosion Control Plan - 2006

Life will return into the waters of Roşia Montană

Mining has been a tradition in Roşia Montană for over 2,000 years, and the mining practices used in the past resulted in the pollution of the soil and surface waters with heavy metals and their compounds. In contact with oxygen and water, sulphur-containing rocks have generated a weak sulphuric acid solution, which has dissolved the heavy metals in the rock and gradually spread into the surface and underground waters, polluting them.

From the very first year of its operations, the project proposed by Roşia Montană Gold Corporation provides for measures to put an end to this historical pollution and improve water quality in the Roşia Montană area.

Rosia Montana watersAcidic waters pollute Aries
  • In Roşia Montană, gold has been mined ever since the Roman Empire. Modern mining requires the rehabilitation of the environment affected by past mining operations, which have left behind a strongly degraded environment.
  • The main source of environmental pollution is acidic water. The exposure of sulphur-containing rocks to oxygen and water results in the formation of a weak sulphuric acid solution, which dissolves the heavy metals in the rock and eventually ends up in the surface or underground waters, without any prior treatment, thus leading to water pollution.
  • From the old mine galleries (totalling around 140 km), 20 litres of acid water drain into the Roşia stream every second, then propagate downstream, along several tens of kilometres, in the Abrud and Aries rivers.
  • Because of these acid waters, the flora and fauna are almost inexistent downstream of the Roşia and Abrud rivers.
  • In the water streams from Roşia Montană, the chemicals concentrations exceed several times the legal limits, as follows: 1.3 times for cadmium, 5.2 times for arsenic, 73.6 x for iron and 96.3 x for zinc.

  • Cadmium and arsenic are among the top seven hazardous chemicals on the CERCLA 2007 (Comprehensive Environmental Response, Compensation and Liability Act – the list of hazardous substances of the US Environmental Protection Agency). For comparison, cyanide ranks only 28th on the same list.
  • A detailed plan for the collection and treatment of the acid rock drainage leaking out of the abandoned mine galleries has been developed as part of the Roşia Montană Project. Additional measures will also be taken to clean up the Roşia and Corna Valleys, so that the water flowing in these streams could sustain aquatic wildlife.

As a result of the implementation of the Roşia Montană Project, not even one drop of contaminated water will leave the project site without prior treatment.

Water management within the Roşia Montană Project includes the following measures:

  • Before the start of the project construction phase, the waters which have not been impacted by historical mining and which will not be impacted by the project will be diverted around the project site, through diversion channels. These channels will discharge the water downstream of the Roşia Montană Project.
  • The acidic waters which are currently flowing freely into the hydrographical system will be collected behind the Cetate acid water catchment dam, and from there, they will be pumped towards the Processing Plant, where they will be treated in an acidic water treatment station.
  • The treated water will be used in the technological process, or discharged in the Roşia and Corna Valleys (downstream of the dams), in order to maintain the ecological flow rate of the 2 streams.
  • Raw water will be supplied from the Arieş River, through a pumping and piping system.
  • Only 15% of the water quantity required for the project will be sourced from the Aries River, while the remaining 85% will be re-circulated from the tailings management facility.
  • Any discharges and runoffs from the Roşia Montană Project sites will be captured and treated before being released in the environment.