Gravel pit

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Gravel pit in Tullingeasen, which forms part of Uppsalaasen. Tullingeasen 2012.jpg
Gravel pit in Tullingeåsen, which forms part of Uppsalaåsen.

A gravel pit is an open-pit mine for the extraction of gravel.

Contents

Gravel pits often lie in river valleys where the water table is high, so they may naturally fill with water to form ponds or lakes. [1] Gravel pit lakes are typically nutrient rich and can support thriving ecosystems, but can also present environmental issues such as the release of toxic metals into watersheds from the exposed rock. [2] Old, abandoned gravel pits are normally used either as nature reserves, or as amenity areas for water sports, landfills and walking. In Germany former gravel or sand pits that have filled up with water are known as Baggersee ("power dug lake") and popular for recreational use. In addition, many gravel pits in the United Kingdom have been stocked with freshwater fish such as the common carp to create coarse fishing locations. Gravel pit lakes have also been stocked with carp in Denmark, as well as rainbow trout. [3]

Products

Gravel pits are a main source of aggregates such as gravel and sand, which are extracted then processed extensively to be suitable for various uses. [4] Aggregates are mined to make concrete, be crushed into construction aggregate, and for other industrial mineral uses. Gravel pits are located where there are rich sources of materials suitable to be crushed into aggregate, often at sites of fluvial, glacial, or floodplain geological deposits. [4] Sedimentary and igneous rocks typically produce good quality aggregates of various sizes, but metamorphic rocks are rarely mined at gravel pits as they tend to have weaker geological structures. [4] The strength of the aggregates mined at gravel pits is important to ensure that the products created using them have good structural integrity.

Production Process

Conveyor operating in a gravel pit. Fleethill Gravel Pit near Yateley - geograph.org.uk - 4965270.jpg
Conveyor operating in a gravel pit.

Once a deposit of aggregate material is located (often in river valleys where rock has been carried downstream and settled overtime) the surface vegetation and topsoil is cleared to reveal the rock. [5] Once a pit is dug into the aggregate, it can be lifted out by bulldozers that load it onto a conveyor or dredged out if the pit fills with water. [5] [6] It is then separated by particle size, crushed, and washed in preparation for use. [5] [6] Washing removes unwanted small particulate matter such as clay, silt, and sand, and is also a safety measure for dust control. [6]

Product Uses

A major direct use of the aggregates produces at gravel pits is road construction. Road structure typically includes pavement and multiple sub-layers of aggregates of increasing sizes with depth beneath the pavement, up to several meters. [7] All the layers of the road structure requires naturally occurring aggregates that are extracted from gravel pits or other surface material extraction sites. [7] [8] Beyond the initial construction of paved roads, gravel pits are important for the ongoing maintenance of unpaved roads because the surfaces of unpaved roads must be continually graded and re-surfaced with new loads of aggregate. [9] In remote regions served by isolated unpaved roads, gravel pit operations are often located at strategic intervals every few hundred kilometers along the roadway in conjunction with road maintenance camps to provide the maintenance crews working out of these camps with the necessary materials. [10] For example, along the Dempster Highway that stretches across the isolated northern region of Yukon Territory, Canada, there are several gravel pits in use for road maintenance and several more that have fallen into disuse. [10] However, most are expected to be put back into operation in the near future as permafrost changes the road structure over time, which is a challenge affecting many isolated roads in the north, and one of the ways that gravel pits are particularly important to remote regions that face unique challenges. [11]

Issues Surrounding Gravel Pits

Environmental Impacts

Gravel pits disrupt the natural processes of the landscapes in which they are operating by displacing vegetation, soil, and rock. [12] This in turn re-routes surface water flow changing runoff patterns, which can create further environmental problems for entire watersheds. [12] Habitats are destroyed, displacing wildlife and removing plants, which changes the ecology of the region. [12] Silica dust caused by aggregate extraction is stirred up and carried in the wind coating plant leaves and minimizing photosynthesis, which not only disrupts natural vegetative processes but also affects agriculture and can therefore disrupt rural economies. [13] [14] Environmental impact assessments must be conducted before such projects to mitigate negative affects, and rehabilitation efforts should be undertaken after projects to restore the natural ecosystem. [12] [15] [16] Unfortunately, most old gravel pits have not been rehabilitated after aggregate extraction has ceased, and their potential to be restored to accommodate improved ecosystem function is wasted. [12]

Abandoned gravel pit filled with water and vegetation regrowth. P.Bialowieska kw. 242A former gravel pit.JPG
Abandoned gravel pit filled with water and vegetation regrowth.

Human Health Impacts

The negative impacts on human health from gravel pit operations are well documented. Both workers of gravel pits and residents close to gravel pits are at risk of pulmonary issues ranging from shortness of breath and airway restriction to chronic obstructive pulmonary disease and silicosis. [17] [14] The culprit of these issues is the fine silica dust created and stirred up by aggregate extraction processes and carried in the wind, which people breathe in and coats surfaces such as nearby homes and plants. [17] [18] There are also concerns that agricultural plants coated in dust from gravel pit operations pose a risk to human health through consumption if the plant contains the dust. [13] There have been widespread movements by communities affected by gravel pit operations to have them moved away to less windy, residential, or agricultural areas, and for better safety precautions to be adopted for worker health. [13] [17] [18]

Gravel pit under restoration. Latest gravel pit - geograph.org.uk - 3556891.jpg
Gravel pit under restoration.

Rehabilitation Potential of Abandoned Gravel Pits

Once a gravel pit site is no longer producing aggregate it will often fall into disuse and be left abandoned. [19] [20] Many become informal recreation sites or transition into wetlands, lakes, or ponds as they fill with water, but remediation can help this process and reduce safety hazards they impose in their industrial state. [20] [21] Remediation programs can be undertaken to build abandoned gravel pits into sites of thriving wildlife habitats, parks or farmland, and/or be flooded and stocked for recreational fishing and to create aquatic ecosystems. [19] [20] [21]

See also

Related Research Articles

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Bitumen is an immensely viscous constituent of petroleum. Depending on its exact composition it can be a sticky, black liquid or an apparently solid mass that behaves as a liquid over very large time scales. In American English, the material is commonly referred to as asphalt. Whether found in natural deposits or refined from petroleum, the substance is classed as a pitch. Prior to the 20th century, the term asphaltum was in general use. The word derives from the Ancient Greek word ἄσφαλτος (ásphaltos), which referred to natural bitumen or pitch. The largest natural deposit of bitumen in the world is the Pitch Lake of southwest Trinidad, which is estimated to contain 10 million tons.

<span class="mw-page-title-main">Road</span> Land route

A road is a thoroughfare for the conveyance of traffic that mostly has an improved surface for use by vehicles and pedestrians. Unlike streets, whose primary function is to serve as public spaces, the main function of roads is transportation.

<span class="mw-page-title-main">Quarry</span> A place from which a geological material has been excavated from the ground

A quarry is a type of open-pit mine in which dimension stone, rock, construction aggregate, riprap, sand, gravel, or slate is excavated from the ground. The operation of quarries is regulated in some jurisdictions to manage their safety risks and reduce their environmental impact.

<span class="mw-page-title-main">Open-pit mining</span> Surface mining technique

Open-pit mining, also known as open-cast or open-cut mining and in larger contexts mega-mining, is a surface mining technique that extracts rock or minerals from the earth.

<span class="mw-page-title-main">Road surface</span> Road covered with durable surface material

A road surface or pavement is the durable surface material laid down on an area intended to sustain vehicular or foot traffic, such as a road or walkway. In the past, gravel road surfaces, macadam, hoggin, cobblestone and granite setts were extensively used, but these have mostly been replaced by asphalt or concrete laid on a compacted base course. Asphalt mixtures have been used in pavement construction since the beginning of the 20th century and are of two types: metalled (hard-surfaced) and unmetalled roads. Metalled roadways are made to sustain vehicular load and so are usually made on frequently used roads. Unmetalled roads, also known as gravel roads or dirt roads, are rough and can sustain less weight. Road surfaces are frequently marked to guide traffic.

<span class="mw-page-title-main">Asphalt concrete</span> Composite material used for paving

Asphalt concrete is a composite material commonly used to surface roads, parking lots, airports, and the core of embankment dams. Asphalt mixtures have been used in pavement construction since the beginning of the twentieth century. It consists of mineral aggregate bound together with bitumen, laid in layers, and compacted.

<span class="mw-page-title-main">Permeable paving</span> Roads built with water-pervious materials

Permeable paving surfaces are made of either a porous material that enables stormwater to flow through it or nonporous blocks spaced so that water can flow between the gaps. Permeable paving can also include a variety of surfacing techniques for roads, parking lots, and pedestrian walkways. Permeable pavement surfaces may be composed of; pervious concrete, porous asphalt, paving stones, or interlocking pavers. Unlike traditional impervious paving materials such as concrete and asphalt, permeable paving systems allow stormwater to percolate and infiltrate through the pavement and into the aggregate layers and/or soil below. In addition to reducing surface runoff, permeable paving systems can trap suspended solids, thereby filtering pollutants from stormwater.

<span class="mw-page-title-main">Surface mining</span> Type of mining in which the soil/rock above mineral deposits is removed

Surface mining, including strip mining, open-pit mining and mountaintop removal mining, is a broad category of mining in which soil and rock overlying the mineral deposit are removed, in contrast to underground mining, in which the overlying rock is left in place, and the mineral is removed through shafts or tunnels.

<span class="mw-page-title-main">Concrete recycling</span> Re-use of rubble from demolished concrete structures

Concrete recycling is the use of rubble from demolished concrete structures. Recycling is cheaper and more ecological than trucking rubble to a landfill. Crushed rubble can be used for road gravel, revetments, retaining walls, landscaping gravel, or raw material for new concrete. Large pieces can be used as bricks or slabs, or incorporated with new concrete into structures, a material called urbanite.

<span class="mw-page-title-main">Gravel road</span> Type of unpaved road surfaced with gravel

A gravel road is a type of unpaved road surfaced with gravel that has been brought to the site from a quarry or stream bed. Gravel roads are common in less-developed nations, and also in the rural areas of developed nations such as Canada and the United States. In New Zealand, and other Commonwealth countries, they may be known as metal roads. They may be referred to as "dirt roads" in common speech, but that term is used more for unimproved roads with no surface material added. If well constructed and maintained, a gravel road is an all-weather road.

<span class="mw-page-title-main">Washboarding</span> Formation of ripples in gravel and dirt roads

Washboarding or corrugation is the formation of periodic, transverse ripples in the surface of gravel and dirt roads. Washboarding occurs in dry, granular road material with repeated traffic, traveling at speeds above 8.0 kilometres per hour (5 mph). Washboarding creates an uncomfortable ride for the occupants of traversing vehicles and hazardous driving conditions for vehicles that travel too fast to maintain traction and control.

<span class="mw-page-title-main">Chipseal</span> Pavement surface treatment

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<span class="mw-page-title-main">Construction aggregate</span> Coarse to fine grain rock materials used in concrete

Construction aggregate, or simply aggregate, is a broad category of coarse- to medium-grained particulate material used in construction, including sand, gravel, crushed stone, slag, recycled concrete and geosynthetic aggregates. Aggregates are the most mined materials in the world. Aggregates are a component of composite materials such as concrete and asphalt; the aggregate serves as reinforcement to add strength to the overall composite material. Due to the relatively high hydraulic conductivity value as compared to most soils, aggregates are widely used in drainage applications such as foundation and French drains, septic drain fields, retaining wall drains, and roadside edge drains. Aggregates are also used as base material under foundations, roads, and railroads. In other words, aggregates are used as a stable foundation or road/rail base with predictable, uniform properties, or as a low-cost extender that binds with more expensive cement or asphalt to form concrete. Although most kinds of aggregate require a form of binding agent, there are types of self-binding aggregate which require no form of binding agent.

<span class="mw-page-title-main">Crushed stone</span> Artificial gravel of angular shape, used as construction aggregate

Crushed stone or angular rock is a form of construction aggregate, typically produced by mining a suitable rock deposit and breaking the removed rock down to the desired size using crushers. It is distinct from naturally occurring gravel, which is produced by natural processes of weathering and erosion and typically has a more rounded shape.

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<span class="mw-page-title-main">Cellular confinement</span> Confinement system used in construction and geotechnical engineering

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<span class="mw-page-title-main">Environmental impact of mining</span> Environmental problems from uncontrolled mining

Environmental impact of mining can occur at local, regional, and global scales through direct and indirect mining practices. Mining can cause erosion, sinkholes, loss of biodiversity, or the contamination of soil, groundwater, and surface water by chemicals emitted from mining processes. These processes also affect the atmosphere through carbon emissions which contributes to climate change.

<span class="mw-page-title-main">Hoggin</span>

Hoggin is a compactable groundcover that is composed of a mixture of clay, gravel, and sand or granite dust that produces a buff-coloured bound surface.

Soil stabilization is a general term for any physical, chemical, mechanical, biological, or combined method of changing a natural soil to meet an engineering purpose. Improvements include increasing the weight-bearing capabilities, tensile strength, and overall performance of unstable subsoils, sands, and waste materials in order to strengthen road pavements.

References

  1. ↑ Deere, Don W.; Hayden, Colby J.; Church, Glen G. (2006-11-03). Gravel Pit Reservoirs — Colorado's Water Storage Solution. American Society of Civil Engineers. pp. 158–173. doi:10.1061/40890(219)12. ISBN   978-0-7844-0890-2.
  2. ↑ Mollema, Pauline N.; Antonellini, Marco (2016-08-01). "Water and (bio)chemical cycling in gravel pit lakes: A review and outlook". Earth-Science Reviews. 159: 247–270. Bibcode:2016ESRv..159..247M. doi:10.1016/j.earscirev.2016.05.006. hdl: 11585/566462 . ISSN   0012-8252.
  3. ↑ Søndergaard, Martin; Lauridsen, Torben L.; Johansson, Liselotte S.; Jeppesen, Erik (2018-01-15). "Gravel pit lakes in Denmark: Chemical and biological state". Science of the Total Environment. 612: 9–17. Bibcode:2018ScTEn.612....9S. doi:10.1016/j.scitotenv.2017.08.163. ISSN   0048-9697. PMID   28846908.
  4. 1 2 3 Eden, M. A.; French, W. J. (2005-01-01). "AGGREGATES". In Selley, Richard C.; Cocks, L. Robin M.; Plimer, Ian R. (eds.). Encyclopedia of Geology. Oxford: Elsevier. pp. 34–43. doi:10.1016/b0-12-369396-9/00254-9. ISBN   978-0-12-369396-9 . Retrieved 2024-02-18.
  5. 1 2 3 "Sand and Gravel Mining Industry | Tern and Plover Conservation Partnership | Nebraska". ternandplover.unl.edu. Retrieved 2024-04-10.
  6. 1 2 3 Cielec, Lynn (2016-09-21). "How Gravel Pits Work". Midwest Industrial Supply. Retrieved 2024-04-10.
  7. 1 2 Davidovic, Nebojsa; Bonic, Zoran; Prolovic, Verka (2012). "Waste glass as additive to clayey material in subgrade and embankment of road pavement". Facta universitatis - series: Architecture and Civil Engineering. 10 (2): 215–222. doi:10.2298/FUACE1202215D. ISSN   0354-4605.
  8. ↑ Surface Material Extraction Pits in Alberta: What Landowners Need to Know (PDF) (Report). Government of Alberta, & Farmer's Advocate Office. May 2019.
  9. ↑ "Gravel Roads: Maintenance and Design Manual". US EPA. 2015-10-14. Retrieved 2024-03-18.
  10. 1 2 "Maintenance Camps - 25k". Government of Yukon. Retrieved 2024-03-18.
  11. ↑ Vucic, Jasmina M.; Cohen, Rachel S.; Gray, Derek K.; Murdoch, Alyssa D.; Shuvo, Arnab; Sharma, Sapna (2019-01-01). "Young gravel-pit lakes along Canada's Dempster Highway: How do they compare with natural lakes?". Arctic, Antarctic, and Alpine Research. 51 (1): 25–39. Bibcode:2019AAAR...51...25V. doi: 10.1080/15230430.2019.1565854 . ISSN   1523-0430.
  12. 1 2 3 4 5 "3. The Environmental Impacts of Aggregate Extraction". Toronto Environmental Alliance. Retrieved 2024-03-22.
  13. 1 2 3 "Can gravel mining and world-class cherry orchards coexist in Utah?". The Salt Lake Tribune. Retrieved 2024-04-09.
  14. 1 2 Nemer, Maysaa; Giacaman, Rita; Husseini, Abdullatif (17 September 2020). "Lung Function and Respiratory Health of Populations Living Close to Quarry Sites in Palestine: A Cross-Sectional Study". Int J Environ Res Public Health. 17 (17): 6068. doi: 10.3390/ijerph17176068 . PMC   7504702 . PMID   32825513.
  15. ↑ "Environmental Impact Assessment of Limestone Quarrying". Collington Winter. 2023-05-04. Retrieved 2024-03-22.
  16. ↑ "Environmental Assessment". BURNCO Aggregate Mine Project. Retrieved 2024-03-22.
  17. 1 2 3 "Study raises health concerns for sand and gravel workers". Spartan Newsroom. 2022-04-29. Retrieved 2024-04-09.
  18. 1 2 "Research lags on residential exposure to dust from sand, gravel mines". WCMU Public Radio. 2023-05-24. Retrieved 2024-04-09.
  19. 1 2 Wisniewski, Dominik (2013-05-30). "The pits in Northumberland". Northumberland News. Retrieved 2024-04-09.
  20. 1 2 3 McCullough, Cherie D.; Schultze, Martin; Vandenberg, J.A. (February 2020). "Realizing Beneficial End Uses from Abandoned Pit Lakes". Minerals. 10 (2): 133. Bibcode:2020Mine...10..133M. doi: 10.3390/min10020133 – via ResearchGate.
  21. 1 2 "The path from pit to paradise". Ducks Unlimited Canada. Retrieved 2024-04-09.
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