Water is the most vital resource for life. Which is why it is important to understand the impact of artisanal and small-scale placer mining (ASM) on water bodies and watercourses and implement the correct water use and management practices. Placer ASM involves several practices, such as: panning, a fully manual processes; semi-mechanized practices involving the use of suction pumps and monitors, and the use of mini dredges.
 Further on we will discuss the impact of mining using backhoes, which we do not consider to be a part of ASM given its ability to move solid materials, the level of financial investment and the fact that it is often related to the illegal extraction of minerals (also called ‘criminal mining’ in Colombia).
Usually, panning takes advantage of superficial deposits on the beaches of creeks, lakes and rivers, and it may be performed by a single person or a small family group. It consists of the extraction and processing of sands and gravels from beaches and rivers with the aid of manual tools such as bars, pans, shovels, swan neck hoes, using the force of the water as the source of power for washing and classification. These sands and gravels are usually washed in the water course itself using only the pan or a small portable sluice box. Sometimes, water is directed from small dams through artificial channels to help generate a current that washes the material.
This is an ancestral or traditional practice of many local communities – in Latin America it is a key component of the livelihood of many vulnerable communities such as ethnic groups of indigenous or African descent. It is also is a very common practice in traditional mining communities in Africa and Asia. Panning has also been a fundamental livelihood for farmers and river peoples. This is a practice that sees a high level of participation by women and the elderly, as well as a fundamental component of the diversified livelihoods of many river communities who combine panning with fishing, agriculture, forest product gathering, pastoralism and small-scale commerce.
Traditionally, panning only uses the force of gravity to recover the gold. In some places such as the Colombian Chocó, miners also use different types of soapwort to separate the precious metal from the jagua or black sands (see picture). Most traditional processing techniques for separating free gold from other minerals use sluice boxes for the first screening of precious metals, and the pan for classification and manual washing of the concentrates (pan gravimetric analysis). The extensive use of pans is a widespread skill among panners, learnt since childhood; it is considered to be cultural knowledge that is passed on from generation to generation, along with the knowledge on how to identify the places where precious metals can be found.
The practice of panning itself does not have a lasting impact on watercourses, since extraction and washing tends to be scattered across large areas. The volume of sediments that washing produces is comparatively low, so that they can be easily absorbed by water-courses.
However, approximately 20 years ago motorized pumps where introduced in many areas where panning was the traditional gold processing method. A motorized suction pump can remove water from the deepest pits, to allow access to the mineral deposit; suction pumps are also used to elevate the mineral from the bottom of a submerged placer deposit to the surface and to conduct water to washing areas that may be far from streams or running water. Motorized pumps also facilitate the removal of placer material from cliffs, slopes and ravines, through the application of a pressurized stream of water on the cliff, also known as monitor.
Water is the main power source to separate gold from sludge and sand, Cauca, Colombia, 2014.
The introduction of the motorized pump implied the beginning of semi-mechanization of traditional panning practices, bringing significant benefits in terms of occupational health, by reducing heavy manual labor. It also improved the productivity of miners and their families by increasing their extraction and mineral processing capabilities.
However, the use of a monitor against mine faces and slopes at the banks of watercourses leads to significant impacts on water courses and bodies, filling them with sediments that affect their environmental quality and reduce their availability for other cultural and economic uses (fishing, cooking, washing clothes, swimming, and river navigation). If the sediment load in the river exceeds its self-cleansing capabilities, this leads to a sediment saturation that impedes the life of fish and other species of flora and fauna in the river on which communities and the river ecosystem depend.
The adequate management of water in motorized pump and monitor-equipped semi-mechanized mines implies setting up an adequate drainage system and a sedimentation pit to allow solids suspended in water to settle before being dumped into the water bodies.
In certain regions, panners use mercury to improve the recovery of precious metals. With this practice, they not only risk their health, that of their children and their communities, but also pollute the water and sediments of watercourses, contaminating the fish that they feed off of as well. Eliminating the use of mercury requires that governments enable panners to have access to mercury-free techniques through technical, legal, organizational and commercial support programs.
This blog is part of a series of three publications. The first one is Water and mining: what does leadership involve? and the next
one will be about the impact and adequate handling of the mini dredges. Do not miss it!
Cristina Echavarria is a geologist, social scientist and development practitioner based in Colombia, from where she works globally. With over 30 years of experience in applied action-research for sustainable development and participatory natural resource management with indigenous and afro Colombian rural communities and artisanal and small-scale miners in South America, Africa and Asia. She is experienced in applying intercultural and gender responsive approaches in mineral rich territories, with emphasis on the social, environmental, supply chain, and governance dimensions of sustainable development.
She works with international agencies, governments, NGO’s, community leaders and mining companies, to enable fair and sustainable deals for all. She was the founding Executive Director of ARM and is currently a member of the Board of Directors. Cristina is also an independent member of the Forum for Corporate Responsibility of BHP and a member of the Mining Dialogue Group in Colombia.