Sand Mining

Primary reference(s)

UNEP, 2019. Sand and Sustainability: Finding new solutions for environmental governance of global sand resources. GRID-Geneva, United Nations Environment Programme (UNEP). Accessed 20 October 2020.

Additional scientific description

The United Nations Environment Programme report on Sand and Sustainability (UNEP, 2019) describes the following materials as being extracted or mined from the natural environment:

• Natural sands are all sands extracted from natural environments.
• Mineral sands are part of a class of ore deposits that contain heavy metals such as ilmenite, zircon, leucoxene, and rutile. Eroded materials from hard rock sources like granite or basalt accumulate on beaches within river systems and on coastlines. It is these beaches from which these valuable materials are extracted for end-use in jewellery; as pigments in paints, plastics, paper, foods; and in electronics.
• Aggregates are crushed rock, sand and gravels used in construction minerals and water filtration.
  • Primary aggregates consist of crushed rock extracted in hard rock quarries by blasting and crushing; and sand and gravel extracted from pits by excavation and crushing, from lakes, rivers and from coastal beaches or dredged from the sea.
  • Recycled aggregates are crushed rock, sand and gravel produced by sorting, crushing and screening of construction and demolition materials.
  • Manufactured aggregates are substitutes to crushed rock, sand and gravel that are produced from wastes from other industries.

The environmental and social impacts of sand extraction are issues of global significance. Eroded materials from hard rock sources, sands and gravels are the unrecognised foundational material of national economies. They are mined all over the world, with aggregates accounting for the largest volume of solid material extracted globally (UNEP, 2014, 2019).

The following is a summary of the environmental degradation caused by sand mining:

• Loss of biodiversity: via pollution and direct impacts on the biophysical integrity of ecosystems (UNEP, 2014). Removing significant amounts of material from dynamic environments like rivers and coasts, and static environments such as quarries, results in widespread environmental change (UNEP, 2014). Marine sand mining via benthic dredging causes changes in water turbidity and results in a net decline in faunal biomass and abundance (Desprez et al., 2010) or a shift in species composition (UNEP, 2014).
• Land losses: both inland through aggregate extraction and river erosion, and coastal through extraction and erosion. Agricultural production could be affected through loss of agricultural land from river erosion (UNEP, 2014).
• Hydrological function: change in water flows, flood regulation and marine currents. River and marine aggregates are the main sources of aggregates for building and land reclamation. Removing sediment from rivers causes the river to cut its channel through the bed of the valley floor both upstream and downstream of the extraction site. This leads to coarsening of bed material and lateral channel instability (UNEP, 2014).
• Water supply: mainly through lowering of the water table and pollution, also marine aggregate needs to be thoroughly washed to remove salt (UNEP, 2014). For example, the removal of more than 12 million tonnes of sand per year from the Vembanad Lake catchment in India has led to the lowering of the riverbed by 7–15 cm/y (Padmalal et al., 2008). Sand mining can lead to a loss of aquifer storage (Kondolf, 1997). The lowering of the water table can affect agricultural production (Kondolf, 1997).
• Climate: directly through transport emissions, indirectly through cement production (UNEP, 2014).
• Landscape: coastal erosion, changes in deltaic structures, quarries, pollution of rivers (UNEP, 2014). Erosion occurs from direct sand removal from beaches. It can also occur indirectly, resulting from near-shore marine dredging, or as a result of sand mining in rivers (Kondolf, 1997). Damming and mining have reduced sediment delivery from rivers to many coastal areas, leading to accelerated beach erosion (Kondolf, 1997).
• Extreme events: decline of protection against extreme events (flood, drought, storm surge) (UNEP, 2014).

Metrics and numeric limits

There is a lack of adequate information on sand mining, which is limiting regulation of extraction in many developing countries (Sreebha and Padmalal, 2011). Access to data is difficult, and data are not standardised. This absence of global data on sand mining makes environmental assessment very difficult (UNEP, 2014).

An estimated 40 to 50 billion metric tonnes of crushed rock, sand and gravel is extracted every year (Steinberger et al., 2010; UNEP, 2014, 2019).

One way to estimate the global use of aggregates indirectly is through the production of cement for concrete (concrete is made with cement, water, sand and gravel) (UNEP, 2014, 2019).

Examples of drivers, outcomes and risk management

Lack of monitoring systems, regulatory policies and environmental impact assessments have led to indiscriminate mining, triggering severe damage to the environment and related ecosystem services (UNEP, 2014).

The absence of global monitoring of aggregates extraction undoubtedly contributes to the gap in knowledge, which translates into a lack of action. As this is a major emerging issue, there is a need for in-depth research (UNEP, 2014).

There is a need to regulate sand extraction in both national and international waters (UNEP, 2014).

Many sand extraction operations in emerging and developing economies are not in line with respective extractives and environmental management regulations. In addition, mining and dredging regulations are often established without scientific understanding of the consequences. For example, the environmental impact of in-stream mining might be avoided if the annual bed load were calculated and the mining of aggregates restricted to that value or less. ‘Sand mafias’, illegal sand extraction and smuggling has been widely reported (UNEP, 2014, 2019). Most sand from deserts cannot be used for concrete and land reclaiming, as the wind erosion process forms round grains that do not bind well (Zhang et al., 2006).

Direct safety risks for those working in this sector and living in the communities where this takes place include industrial accidents such as drowning of workers removing sand from riverbeds; health effects of particulate (dust) and hydrocarbon pollution; forced child labour; transport accidents; subsidence and landslides in extraction areas (Asolekar, 2006; Maya et al., 2012; UNEP, 2014, 2019).

The training of architects and engineers, new laws and regulations, taxation and positive incentives are required in order to lower the dependency on sand. Renewable and recycled materials need to be targeted for building houses and roads (UNEP, 2014).