The Group is subject to the environmental laws and standards in force in Mozambique, together with international standards and guidelines of the World Bank, AfDB and FMO, as well as its own policies, and consistently seeks to apply best practice in all of its activities.
Kenmare is required to comply with standards in relation to emissions, effluent treatment, noise, radiation, water quality and rehabilitation. Kenmare is committed to the management of its operations in accordance with these environmental laws, standards and its own internal policies. Kenmare is also undertaking a review of compliance at the Mine with IFC Performance Standards and plans to adopt these standards in due course. In addition, Kenmare provides staff with training so that employees at all levels recognise and are able to fulfil their environmental responsibilities.
The Environmental Management Plan (EMP) for the Mine sets out the monitoring activities, management and training programs, reporting activities, auditing and mitigation measures required to identify and reduce any negative impacts of the Mine and to comply with applicable environmental laws and guidelines. Senior management regularly reports to the Board on the status of compliance with the Group’s environmental and social obligations, and aims to ensure that the EMP is properly implemented and maintained.
- Conduct regular performance reviews and legal compliance audits and act upon the results to ensure compliance with national laws and Company policy;
- Provide adequate resources, staff and training so that employees at all levels recognise and are able to fulfil their responsibilities; and
- Develop, maintain and test emergency procedures in conjunction with the relevant authorities.
As the mining face advances, the rear of the mining pond fills with sand tailings from the WCP to a level similar to the pre-existing land surface. This sand is contoured and then covered with a layer of clay-rich material which is mixed into the sand. The additional clay helps the subsoil to retain moisture and nutrients. Finally, topsoil containing seeds, organic material and microorganisms is stripped from the active mining area and placed onto the subsoil. The rehabilitation will be completed by fertilising and seeding with a variety of native or endemic species. Trials are under way to determine the combination of plants most suitable for rehabilitating the mining area, which will include both native flora and food crops. Kenmare is working with the WWF to identify the optimum revegetation strategy. To this end, a nursery area has been established to investigate the optimum conditions and plants for rehabilitation of the area. The slimes dam and the initial tailings stockpile area are part of the trial area.
The total area to be affected by the mine, separation plant and associated infrastructure is approximately 2,829 hectares, of which the mine path is 2,500 hectares. Given that clearing, mining, tailings disposal and land rehabilitation begins one year after mining and can be completed in a five to six year cycle, approximately one third of the mining area or 800 hectares will not be available for agricultural purposes at any one time.
Rehabilitation of mining areas commenced in 2009. Plant and infrastructure areas can be rehabilitated only after closure of the operation.
The great majority of the waste tailings material comprises sand, silt and clay particles removed from the ore in the WCP. These can be sub-divided into sand tailings (>0.045 mm) and slimes (<0.045 mm), which are collected in a series of hoppers at the back of the WCP. Disposal of sand sized particles is straightforward, these being pumped to the rear of the pond and deposited by means of cyclones which are located on top of a mobile stacker.
Disposal of slimes material is more complex, given the propensity for this size fraction to remain in suspension for longer periods. A significant proportion of the slimes fraction is incorporated between sand grains in the sand tailings and needs no further management. Excess slimes in the tails are allowed to consolidate in settling ponds, and are then pumped as thick slurry to drying cells. Over the following months, the water evaporates from the slurry, leaving low moisture clay that can be easily moved and handled. This material will be placed into the subsoil during rehabilitation of the dredge path, providing benefits for the subsequent revegetation.
Sand tailings consisting of non-valuable minerals are also generated by the MSP. These are returned to the mining void from which they originated, and are buried under the inert sand tailings from the WCP.
Water for the Mine is supplied from an aquifer via twelve boreholes and from a lake. Water is mainly used in the dredge pond and processing plants as well as for domestic use. The aquifer recharges each year with rainfall.
A water monitoring programme, which has been approved by the Mozambique authorities under a separate document from the EMP, continues to be followed. A total of eleven surface water sites, six community water wells, six ground water sites and four internal drinking water sites are regularly monitored for a wide range of constituents.
Effluents, Sewage and Waste Water Handling Facilities
Sewage treatment plants have been provided for the MSP, WCP and accommodation village. The treatment plants each comprise a collector tank and pumping station, aerobic treatment unit, agitated aeration tank and sludge disposal to a sludge digestion pond.
Non-Hazardous Solid Wastes
Solid wastes include materials from the workshop, laboratory and domestic sources. A solid waste disposal facility has been provided, including a lined area for non-inert material.
This may include liquid waste from the laboratory and hydrocarbon-contaminated material from the workshops. These are disposed at an approved hazardous waste disposal site.
Electrical power is used for the dredges, WCP, tailings and slimes disposal pumps and MSP, as well as offices and the accommodation village. This is sourced from the national grid by means of a 110 kV overhead transmission line from the substation at Nampula. The power is generated by the hydro-electric dam at Cahora Bassa. A small on-site diesel power station has been constructed to supply back-up power for critical equipment in the event of power outages. This power station is rated at 6 MW and is capable of supplying the MSP and other key equipment (but not the mining operation) during an extended grid outage.
Emissions and Air Quality
A monitoring programme has been designed for the MSP which records ambient meteorological conditions, as well as the primary anticipated pollutants (inhalable particulates, total particulate matter, CO, CO2, NO and SO2). Dust monitoring of all areas were within the specified standards. All the bag-houses at the MSP are operational and no out of standard readings were recorded.
A workplace noise monitoring survey was carried out. The results of the report indicated that the workplace at the MSP is above the 85 dB(A) threshold value and hence hearing protection in the MSP is mandatory. All areas are signposted, hearing protection is provided, and wearing is enforced.
Noise levels at the property boundary were measured during the workplace noise monitoring. Kenmare is in compliance with the stipulated requirements for different times of the day and night as well as during public holidays.
Radioactive elements such as uranium and thorium occur naturally, in very small quantities, in most heavy minerals including those mined by Kenmare. The presence of radioactive elements in the heavy minerals results in a natural level of radioactivity in the region. The extraction and processing of the heavy minerals merely concentrates naturally-occurring radioactive minerals; no radioactive substances are created by mining or processing.
The standards used for radiation protection for the Mine are the international standards recommended in the Basic Safety Standards of the International Atomic Energy Association. Under these standards, public exposure may not exceed 1 millisievert per annum (mSv/a), while occupational exposure to employees may not exceed 20 mSv/a. All areas monitored are within these limits.
Top of page