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CLOSE THIS BOOKEnvironmental Impacts of Small Scale Mining (CEEST, 1996, 62 p.)
VIEW THE DOCUMENT(introduction...)
VIEW THE DOCUMENTList of Abbreviations
VIEW THE DOCUMENTExecutive Summary
1. Introduction
2. Artisanal Mining Activities
3. Artisanal Gold Mining
4. Small Scale Gemstone Mining
5. Environmental Legislation
6. Training in Environmental Issues
VIEW THE DOCUMENTAppendix I: Trip Notes
VIEW THE DOCUMENTAppendix II: The NEMC (1983) Act
VIEW THE DOCUMENTAppendix III: Toxicity of Metals
VIEW THE DOCUMENTAppendix IV: Scope of Work and Methodology
VIEW THE DOCUMENTAppendix V: List of Persons Met

Executive Summary


In terms of Government revenue, Tanzania's mining sector has been growing since 1990 the main reason being the sudden surge in gold production countrywide. Besides the fact that this country has substantial gold reserves, increase in gold production was came in the wake of macro-economic reforms and particularly, the introduction of new arrangements in the marketing of gold and the attractive prices offered by the Bank of Tanzania (BOT). BOT is presently vested with the responsibility of buying all the gold produced in the country, although this responsibility is likely to shift away from the Central Bank to an appropriate commercial organization.

Since 1991, all gold in the country has been produced within the informal mining sector or by artisanal miners involved in the mining of gemstones, gold and diamonds and which are estimated to number in excess of 300, 000. From only the few kilograms before 1990, gold production has increased to over 3.0 tons annually to-date. However, the word 'increase' should be treated with caution here since the informal mining sector existed in the country prior to 1990 (albeit illegally), and was apparently involved in substantial smuggling activities.

Parallel with the ongoing artisanal mining activities is the extensive environmental degradation caused by inefficient mining and the poor processing technologies currently being employed (by miners), and the lack of effective environmental monitoring, regulations and legislation.

The purpose of this report is to make an assessment of the extent of environmental impacts caused by artisanal mining activities in selected areas. In accordance with the terms of reference, the areas studied (and which represent a great deal of artisanal mining activities in Tanzania), are Merelani (for gemstones), and Mara, Nzega, Kahama, Geita and Musoma (for gold).

The recommendations put forward in this report are targeted to unveil the extent of environmental degradation created by artisanal mining activities on the land, air and in water. This environmental impact assessment (EIA), it is hoped, will result in an increased awareness on the part of those directly concerned with the mining sector. Subsequently, it is hoped that the need to prepare an Environmental Action Plan for Implementation aimed at averting further environmental destruction - the human habitat - which would therefore ultimately lead to the destruction of human lives.


Artisanal or small scale subsistence mining is a fast growing sector in Tanzania. The Bank of Tanzania on collaboration with its other banking institutions such as the Co-operative and Rural Development Bank and the National Bank of Commerce are currently purchasing about 3.5 tons of gold annually from artisanal miners whose worth amounts to about US $40.0 million. As a result, Government revenue from gold has multiplied several times over in comparison to a paltry US $1.2 million obtained in 1990. These figures exclude illegal exports.

Gold that used to leave the country through unscrupulous illegal dealers is now tapped by the Government due to:-

(i) the better prices offered to the miners by the Bank of Tanzania; and
(ii) an organized marketing system.

The above notwithstanding, however, the benefits accruing from the activities of artisanal miners are overshadowed by the adverse environmental effects caused by these very activities - some of which maybe irreversible.

2.1. Environmental Aspects

Field observations have essentially identified the major causes of environmental destruction to be the following:-

· Dust

This is a product emitted during rock drilling either in charging explosives used for blasting or fragmenting ore. This is rampant in the gold mining areas particularly where reefs are being worked. The nature of the dust consists mainly of silica which may ultimately develop silicosis or "widow maker" as it is popularly known. Similarly, tanzanite mines in Merelani emit carbon dust (due to existence of a graphite horizon as country rock).

During ore preparation in the recovery of gold, the ore-crushing method consists of a car axle (which acts as a pestle) being pounded into a wooden mortar several times over a long period. This labourious job in turn produces a lot of siliceous dust which is directly inhaled by the miners thereby posing a potential health hazard.

· Mercury

The gold recovery process involves a number of stages, the main ones being: crushing, grinding, amalgamating with Mercury and finally heating the amalgam to drive off the Mercury from the gold (which is then ready for sale).

It was observed that the washing and panning of amalgam is conducted mainly alongside and inside rivers. This methodology of handling Mercury results in river water, streams and water wells getting polluted. Besides, this practice also causes silting.

Water samples taken in several locations and analyzed by the Government chemist have revealed staggering levels of Mercury in them. Samples which showed the highest Mercury level in water were from Mugusu (Geita District), which measured 2.306 micrograms per litre. Drinking water from Ushirombo (Kahama District) measured 0.106 microgram per litre, the lowest. These values are rated as being very high for effluents meant for direct discharge in receiving waters given that the maximum permissible level is only 0.005 microgram per litre. In addition, water for domestic use should record zero Mercury values.

The Bank of Tanzania which has been given the mandate to sell Mercury has sold around the Lake Victoria zone 1, 474.30 kilograms of Mercury since 1990-June, 1993. It is important to mention here that the impact of Mercury pollution can be felt several thousand kilometres downstream. Essentially, this means that artisanal mining activities which actually surround Lake Victoria may already have started polluting it to the detriment of the millions of people depending on it and not discounting the far-reaching ramifications on the Nile river itself.

· Pit Excavation

Reaching the ore body involves digging deep excavations ranging between anything from 10 to 100 metres. The number of mine pits in any one location is anywhere between 100 and 1, 000 in a closely knit "honeycomb" structure many of which are inactive yet having been abandoned without being refilled or adequate protection provided. Along with this are large stockpiles of excavated materials which have not been removed but left around the mine pits. These materials could be used for refilling.

This uncontrolled digging of thousands of pits in the mining areas has caused the massive destruction of land. Of equal importance and consideration is that these pits are not refilled nor is the land properly reclaimed to enable other economic activities once the mineral resources have been depleted or abandonment due to technical reasons or on economic grounds.

It is therefore recommended that:-

(i) Simple, appropriate but more advanced technologies should be employed in order to minimize or eliminate the emission of dust during ore extraction or during ore processing caused by the poor technologies currently employed by the artisanal miners in the mining of valuable minerals.

A technical audit which culminates in the production of a study on the technological needs appropriate to artisanal miners should be carried out.

(ii) As the continued use of Mercury in gold recovery has far-reaching environmental repercussions, NEMC, in conjunction with the Mineral Resources Division (MRD) of the Ministry of Water, Energy and Minerals should carry out periodic checks on rivers, streams and wells in the artisanal mining areas to determine levels of toxicity.

(iii) On the technology side, a study aimed at identifying simple appropriate recovery methods which should result into economizing the use of Mercury, instituting Mercury's efficient recovery and at the same time saving the environment from being continuously polluted.

(iv) The need to refill the many mine pit excavations resulting from actual mining, them after mining activities was emphasized. The Mineral Resources Department through Zonal mines officers should be made responsible, through mining regulations, to ensure that excavations are refilled/maintained. Some active mining areas or abandoned sites require that permanent protection be installed (in the form of steel fencing, rock walls or concrete covers).


Tanzanite mining at Merelani is undertaken in a manner similar to gold mining. A number of mining pits are excavated in order to reach the tanzanite horizon. Pit depths are in the region of 50-100 metres. However, it was observed that no chemicals were used in the process of recovering this valuable gem.

3.1. Environmental Aspects

The main environmental degradants comprises the hundreds of mine pit excavations of which a large percentage are inactive and have not been refilled. No protection is provided to both active and inactive mines. It is therefore recommended that all abandoned inactive mine pits be refilled and/or protected. The Mineral Resources Department should oversee and ensure that this exercise is carried out within the constraints which are currently being faced by the claim holders such as the financial constraint, and the lack of equipment.


At present, the Government policy on all forms of mining falls under the Ministry of Water, Energy and Minerals and is governed through the Mining Act, 1979 and supported by various mining regulations such as the following:-

(i) The Mining (Claims) Regulations relating to claims which applies to Tanzanian citizens.

(ii) The Mining (Prospecting Rights) Regulations which concerns prospecting activities by Tanzania citizens.

(iii) The Mining (Minerals Rights) Regulations which apply to foreign and local companies which deal with a sequence of reconnaissance and exploration, and mining licenses for large-scale/formal mines.

(iv) The Mining (Royalty) Regulations which is targeted at raising Government revenue by getting a portion/percentage of the mineral sales.

Whereas the Mining Act 1979 is silent on environmental issues, the Mining (Claims) Regulations contain sections which dwell on environmental controls. In particular, Article 13 underscores the obligations of a claim holder when abandoning a mining pit. An essential feature is that all shafts, pits and excavations should be filled up or fenced.

Article 23 dwells on the conditions and preconditions for the deposit of tailings; particularly "those which may terminate in any water-course. However, no mention of standards is made.

On the other hand, the Government formed the National Environment Management Council in 1983 whose main functions are to formulate policy, co-ordinate activities and evaluate existing and proposed environment management policies. As such, it is in a state which can be described as a "toothless bulldog" which can only bark but is not allowed to bite. The biting part is assumed to be the job of the Minerals Resources Department.

Despite the provisions of the Mining (Claim) Regulations 1980, as stated above, there appears to be no action on the part of those concerned to stem the ever-increasing artisanal mining activities and the apparent environmental destruction that is continuing without any sort of obstruction. It is therefore my view that the existing environment regulatory regime is ineffective to deal with this otherwise insurmountable problem.

It is therefore recommended that:-

· Institutional capabilities should be strengthened to create an enabling environment for the Minerals Resources Department with the possible participation by the National Environment Management Council, miners associations and co-operatives and the various claim holders. This multi-disciplinary approach would assist in increasing awareness on environment issues to all parties concerned. This would also serve to avoid duplication of work.

· All streams, rivers and lakes in the vicinity of artisanal mining activities, where chemicals such as Mercury or cyanide are employed, should be periodically checked.

· It is further recommended that a separate study on the health of the artisanal mining communities be conducted to determine the extent of damage. This should also include the determination of Mercury levels in marine species such as fish in the streams, rivers, and in Lake Victoria.

· Due to the complexities involved in dealing with the artisanal miners, the government could consider setting up a "Reclamation Fund" to assist claim holders with the immense task of land reclamation.


It has been elucidated that the training of small scale miners (particularly on environment issues), is lacking. This fact has manifested itself in the continued land degradation resulting from mining activities. Perhaps this is so because those who are expected to impart knowledge to the miners are themselves not really trained in environmental studies (i.e. environmental studies were not part of their core subjects).

It is therefore recommended that:-

· There is an urgent need for zonal mines officers to conduct seminars and workshops intended for small scale miners that place particular emphasis on environmental education. This could be done in the field or at the Madini Institute in Dodoma in the form of short courses. Formal University/College courses should be provided to engineers and officers at ministerial level.

· Deliberate steps to introduce large posters that dwell on environmental issues (as a way of motivating the miners to go the 'green' way during mining activities) should be taken.