Ambatovy is among the largest mines and integrated metallurgical sites in the world, with an annual capacity of 60,000 tonnes of nickel and 5,600 tonnes of cobalt. In operation since 2014, it is one of the most ambitious industrial undertakings in the history of Madagascar, Africa, and the Indian Ocean Region.
The project is dispersed over a wide area of eastern Madagascar: its mining operations take place in a remote area of rain forest approximately 80km east of Madagascar’s capital Antananarivo. A 220 km long slurry pipeline carries ore from the mine to a processing plant and refinery located 11 km outside of the coastal city of Toamasina, Madagascar’s main port. A further 15 km of slurry pipeline carry tailings from the plant to a permanent storage facility in the port area.
HGC Engineering was retained by SNC-Lavalin to undertake an Environmental Noise Impact Assessment of the three separate operational areas (Mine, Plant, and Port Sites) of the Ambatovy project prior to construction. The assessment was required in order to demonstrate compliance with the environmental noise impact guidelines of the International Finance Corporation (“IFC” of the World Bank Group)
Sound power emission levels for each item of equipment at each of the three operational sites were obtained either from manufacturer’s published sound levels, past measurements of similar equipment by HGC Engineering, or generic predictions based on the size and capacity of the equipment. These source levels were used along with geometrical and topographical information about the sites and surrounding areas to develop a predictive acoustical computer model, in order to compute the offsite sound levels in advance of construction and to assess the environmental sound emissions of each site. Our overall analysis indicated that the majority of equipment at the three sites did not require special noise control measures but for some key sources we provided acoustical performance specifications as appropriate to comply with IFC/World Bank environmental noise guidelines.
The noise producing equipment and activities at the Mine Site are typical of a large open mine operation, including quarry drills, diesel generators, ore crushers and the movement of on-site vehicles.
The analysis showed that the sound emissions of the proposed Mine Site would be within IFC/World Bank environmental noise guidelines at the neighboring residences, and at the concession boundary of the mine, without any special noise control measures beyond standard Industrial grade mufflers for the generators.
At the Plant Site, noise generating sources include crushers, screeners, pumps, agitators, diesel generators, and the movement of on-site vehicles. The analysis indicated that without any special noise control measures, the sound levels would be within the IFC/World Bank sound level limits at the neighboring residences, but could exceed those criteria at the Plant boundary. Recommendations were provided for engineered noise control measures including:
- The use of local acoustical enclosures around the majority pumps, motors, agitators, and related equipment.
- Housing area crushers and screeners in buildings
- Upgrading the Industrial Grade engine exhaust mufflers of the Plant’s diesel generators.
- Equipping the cooling/ventilation-air opening through the walls of the generator building with pre-fabricated duct silencers
- Constructing a 5 metre-high acoustical wall surrounding the entire Plant Site, at the fence line, in order to reduce the overall noise at the property line considerably and minimize the need for localized acoustical enclosures
The stationary noise considerations at the Port Site include diesel generators, conveyors, dust collectors and compressors, with the majority of activities occurring outdoors. Without any special noise control measures, our analysis indicated that there was a possibility of minor excesses at existing neighboring residences. Like at the plant site, the proposed diesel generators required upgraded exhaust mufflers and ventilation-air silencers
Acoustical Engineering Services Included:
- Employed predictive analysis to determine the anticipated offsite sound levels in the neighbouring residential communities, resulting from the future operations of the facility.
- Evaluated the anticipated sound levels with respect to environmental noise impact guidelines of the International Finance Corporation (“IFC” of the World Bank Group).
- Identified whether noise control measures were likely to be needed, and provided acoustical performance specifications for such measures, as appropriate.