Ghaghoo Diamond Mine Social & Environmental Impact Report
Gope Exploration Company (PTY) LTD
6.2.10. Air Quality
This section outlines the methods that may be employed to mitigate the impacts predicted to take place as a result of the proposed plant and mining operations.
Air quality management of on-site activity, although geared at the reduction of off-site impacts, can also be a measure of improving occupational exposure. The following sections details best management practice principles which should be deployed in order to best manage the air quality impact resulting from on-site activity.
The management control measures are outlined as follows:
- Watering of road surfaces;
- Treatment of suitable surfaces with dust suppressant agents;
- Management of vehicle speed;
- Rehabilitation of exposed surfaces where practicable, and
- Avoid unnecessary storage of material on site.
The watering of roads reduces the amount of dust generated as a result of vehicle entrainment. As the amount of water required may vary from month to month due to the changes in potential evaporation rates for that period, the rate of water application would need to be altered for each month of the year. In the event that the acquisition of water for the use as a dust suppressant is not possible, the following alternative methods can be deployed:
- Chemical suppression: Although water is still required for the making of the mixture, the frequency of application will reduce, thus the amount of water required will also reduce proportionately. Some of the chemical suppressants readily available for use in South Africa are Dust-A-Side, SDS 2 and SDS 4 supplied by 3M, Soiltac® and Durasoil® supplied by Soil and Dust Solutions, etc.; j
- Application of gravel: This will result in the reduction of available silt which can be entrained by vehicles making use of these roads, however continued maintenance by the reapplication of gravel periodically would be required in order to ensure the maximum control efficiency is achieved;
- Tarring: This is listed as an option, although it is recognizes that this would not be the most practical or cost effective measure to limit entrained dust from these sources, especially due to the transient nature of mining haul roads;
- Reduction of vehicle speed (setting a maximum speed limit inside the CKGR).
The minimum amount of material required should be stored in stockpiles and piles should not be left to stand for very long periods. The erection of wind breaks / fences is an additional method of controlling wind blown dust at storage piles. The windbreak should ideally be as high as the storage pile and placed with reference to prevailing wind conditions.