Key Terms in Quarrying and Mining
Quarrying and mining involve specialized terms that are essential for understanding the technical and operational aspects of the industry. Below is a comprehensive glossary of terms commonly used in quarrying, complete with detailed explanations.
Aggregate
Aggregate refers to particles of rock or inorganic material used in construction. These particles, when bound together with cement, asphalt, or left unbound, form the building blocks of roads, buildings, and other civil engineering structures. Aggregates are categorized into fine (e.g., sand) and coarse (e.g., gravel or crushed rock) and are selected based on their physical and mechanical properties to suit specific project requirements.
Aggregate Crushing Value (ACV)
The ACV is a measure of the resistance of aggregates to crushing under gradually applied compressive loads. It indicates the strength of the aggregate, with lower values representing higher resistance. The ACV is critical for assessing aggregate suitability for high-load applications like road bases and railway ballast.
Alkali-Silica Reaction (ASR)
This is a chemical reaction that occurs in concrete when alkalis in cement react with silica in certain types of aggregate. The result is the formation of a gel that swells in the presence of moisture, leading to cracks and structural deterioration. ASR mitigation involves using low-alkali cement, non-reactive aggregates, or supplementary materials like fly ash.
All-in Aggregate
All-in aggregate is a mixture of fine and coarse aggregates that can be used directly without additional blending. It simplifies the batching process in applications like road bases or subgrade layers, where uniformity and compaction are critical.
Alluvium
Alluvium describes unconsolidated sediments such as clay, silt, sand, and gravel deposited by rivers and streams. These materials are sorted or semi-sorted and are often found in floodplains, deltas, or stream channels. Alluvial deposits are a common source of construction aggregates due to their accessibility and workability.
Approved Code of Practice (ACOP)
ACOPs provide practical guidance for complying with regulations under the Health and Safety at Work Act. These documents outline best practices, safety measures, and operational standards to reduce risks in quarrying and other industrial settings.
Apron Feeder
An apron feeder is a heavy-duty machine consisting of steel pans attached to chains. It regulates the flow of materials from a hopper or stockpile to a processing plant by adjusting speed and material depth. This equipment is crucial for handling abrasive and heavy materials like rock or ore.
Aquifer
An aquifer is a permeable geological formation capable of storing and transmitting water. Quarrying near aquifers requires careful management to prevent contamination and ensure sustainable water extraction. Aquifers are tapped through wells and play a critical role in water supply systems.
Argillite / Mudstone
Argillite, also known as mudstone, is a sedimentary rock composed primarily of hardened clay minerals. It is blackish and lacks visible lamination. Due to its brittle nature, it is generally considered of inferior quality compared to other quarried materials like limestone or granite.
Armour Rock / Rip Rap Rock
Armour rock consists of large, irregular lumps of hard rock used in coastal and riverbank defences. These rocks prevent erosion by absorbing wave energy and stabilizing slopes. They are commonly used in engineering projects requiring durable and weather-resistant materials.
Assessment of Environmental Effects (AEE) / Environmental Impact Assessment (EIA)
An AEE or EIA is a comprehensive study evaluating the potential environmental consequences of a quarry or construction project. It assesses impacts on biodiversity, water resources, air quality, and nearby communities. These assessments guide the planning process and inform mitigation strategies.
Basalt
Basalt is a fine-grained igneous rock formed from rapidly cooled lava. Known for its high strength and durability, it is widely used in construction for aggregates, railway ballast, and pavement materials. In some regions, basalt is the second most commonly quarried rock after limestone.
Basecourse
The basecourse is the layer in road construction situated between the subbase and the surface layer. It provides structural support and ensures load distribution. Basecourses are typically composed of crushed aggregates meeting specific grading and compaction standards, such as GAP40 in New Zealand.
Batching Plant
A batching plant houses equipment for accurately measuring and combining raw materials to produce concrete. It ensures the correct proportions of cement, aggregates, water, and admixtures for consistent quality. Advanced batching plants are often automated for precision and efficiency.
Batter
A batter is a uniform, steep slope constructed in quarrying or roadworks. Its incline is expressed as a ratio of horizontal to vertical units (e.g., 1:2). Properly designed batters prevent erosion and ensure stability in earthworks.
Benches / Berms
Benches, or berms, are horizontal levels or steps cut into a quarry face. They facilitate safe working conditions by limiting the height of vertical faces, providing access for equipment, and minimizing rockfall risks. Benches are integral to staged extraction and site stability.
Blast
Blasting involves the detonation of explosives to fracture rock in a controlled manner. This process is essential for extracting hard materials that cannot be mechanically excavated. Effective blast design considers rock type, desired fragmentation, and safety.
Bund
A bund is an earth embankment constructed around a quarry or industrial site to contain materials, control runoff, or reduce noise and visual impact. Bunds are also used as safety barriers to protect workers and equipment.
Certificate of Competence (CoC)
A CoC is a regulatory requirement for managing quarry operations. B Grade Quarry Managers can supervise up to four workers, while A Grade Quarry Managers have no restrictions on team size. Obtaining a CoC involves meeting academic, practical experience, and character criteria, followed by an oral examination.
Clay Index / Methylene Blue Test
This laboratory test estimates the proportion of expansive clay minerals in a sample. High clay content can affect the performance of aggregates in concrete or road construction. The test guides material selection and processing.
Cleanfill / Hardfill
Cleanfill refers to uncontaminated, non-hazardous material like soil, clay, or broken concrete used for land reclamation. Hardfill includes similar materials but may also encompass construction and demolition waste with stricter management requirements.
Compressive Strength
Compressive strength is the capacity of a material to withstand axial loads that tend to reduce its size. For aggregates and rocks, this property determines their suitability for use in construction, particularly in structural applications such as foundations and pavements.
Concrete Aggregates
Concrete aggregates are specially graded materials, such as crushed rock or washed sand, used in concrete production. The quality and gradation of these aggregates directly influence the strength, durability, and workability of the concrete mix.
Contamination
Contamination refers to the presence of unwanted substances within materials such as cleanfill, hardfill, or aggregates. Contaminants can include hazardous chemicals, organic matter, or debris that compromise the quality and safety of construction projects. Proper testing and quality control measures are essential to prevent contamination from impacting structural integrity or the environment.
Conveyor
A conveyor is a mechanical device used to transport materials in a continuous stream. Typically consisting of a rubber or metal belt stretched over rollers, conveyors are commonly used in quarrying to move aggregates efficiently from the excavation site to crushers, stockpiles, or loading areas. Advanced conveyors can include weight sensors and automated controls to optimize material flow.
Crushing
Crushing involves mechanically reducing large rocks into smaller, usable sizes. Various types of crushers serve different purposes: jaw crushers handle primary reduction, cone crushers refine materials further, and impact crushers produce finely shaped aggregates. Crushing is integral to producing materials like concrete and asphalt aggregates.
Cut and Fill
Cut and fill is a surface mining technique where overburden or waste material removed during excavation is used to fill voids created by mineral extraction. This method minimizes waste and stabilizes the site, reducing the need for external disposal areas. It is a common practice in quarries located in environmentally sensitive regions.
Decibel (dB)
A decibel is the unit used to measure sound levels. Noise generated during quarrying—such as from blasting, heavy machinery, or crushers—can reach high decibel levels, necessitating noise management measures like sound barriers and mufflers. Workplace exposure limits are regulated to protect workers from hearing damage, typically capped at 85 dB(A) over an 8-hour shift.
Density
Density is the mass per unit volume of a substance, expressed in kilograms per cubic meter (kg/m³). For quarried materials, density values can vary depending on whether the rock is in its solid (in situ), loose (after extraction), or compacted state. Understanding density is essential for estimating material quantities and ensuring structural stability.
Diamond Drilling
Diamond drilling, or core drilling, uses a hollow bit embedded with industrial diamonds to bore through rock, producing cylindrical cores for analysis. It is a precise method often employed during geological surveys to assess a site’s mineral content, structural integrity, and suitability for quarrying operations.
Dragline
A dragline is a type of excavator with a long boom and a suspended bucket. The bucket is dragged across the ground to scoop up material and then lifted for deposition elsewhere. Draglines are particularly effective for excavation below the level of the machine, making them suitable for extracting loose materials like sand and gravel.
Drill and Blast
Drill and blast refers to the process of drilling holes into rock formations, filling them with explosives, and detonating them to fragment the rock. This method is used in hard-rock quarries where material cannot be easily excavated. Proper blast design ensures efficient fragmentation while minimizing fly-rock, vibration, and environmental impact.
Dumper
A dumper is a self-propelled vehicle used to transport and deposit material. These off-highway machines are designed for rugged terrain and large loads, making them indispensable in quarrying operations. Dumpers are often used in tandem with excavators or loaders to move material from the extraction site to processing facilities.
Dust
Dust in quarrying refers to fine particles generated during excavation, crushing, and transportation. Dust control measures, such as water sprays, enclosures, and air filtration systems, are vital to protect workers’ health and prevent environmental contamination. Dust with particles smaller than 5mm is often categorized separately for regulatory purposes.
Excavator / Digger
Excavators, also known as diggers, are versatile machines equipped with a rotating upper structure and a bucket attached to a boom. They are used for a range of tasks, including excavation, loading, and site preparation. Excavators can be mounted on tracks or wheels, allowing them to operate in various terrains.
Explosives Store / Magazine
An explosives store or magazine is a certified facility for safely storing explosive materials used in blasting. These storage units are designed to meet stringent safety regulations, including secure construction, controlled access, and compliance with hazardous substances laws. Proper storage minimizes the risk of accidents and ensures regulatory compliance.
Face
A quarry face is the vertical or near-vertical surface exposed during excavation. It represents the area from which material is being extracted. Quarry faces are carefully managed to ensure stability and safety, with angles adjusted based on the competence of the rock.
Fly-Rock
Fly-rock refers to fragments of rock that are propelled beyond the designated danger zone during blasting. This phenomenon can occur due to poor blast design or unexpected weaknesses in the rock. Fly-rock poses significant safety risks, necessitating rigorous planning and monitoring of blast operations.
Gabion / Gabion Basket
A gabion is a wire cage filled with rock, used for erosion control, slope stabilization, and architectural features. Gabion walls are permeable, allowing water to pass through while retaining soil and resisting erosion. They are commonly employed in civil engineering and landscape design.
Gradation
Gradation describes the distribution of particle sizes in an aggregate sample. Well-graded aggregates contain a mix of particle sizes, ensuring good compaction and strength. Poorly graded aggregates, with uniform particle sizes, may lead to voids and reduced structural integrity.
Grader
A grader is a machine used to level and smooth surfaces, particularly haul roads in quarries. It features an adjustable blade that can tilt and angle to achieve precise grading. Maintaining well-graded roads ensures efficient transportation of materials and reduces wear on vehicles.
Groundwater
Groundwater refers to water stored within the pores and fractures of subsurface rock layers, up to the water table. Quarrying activities must manage groundwater carefully to prevent contamination and excessive drawdown. Groundwater monitoring is often mandated as part of environmental compliance.
Hard-Rock Quarry
A hard-rock quarry extracts solid rock, typically requiring drilling and blasting to loosen material for excavation. These quarries often feature multiple benches to maximize resource recovery and ensure operational safety. Materials extracted include granite, basalt, and limestone.
Hazard
A hazard in quarrying is any condition or activity that poses a risk of harm to people, property, or the environment. Examples include unstable faces, equipment malfunctions, and exposure to dust or noise. Effective hazard management involves identifying, assessing, and mitigating risks.
High-Hazards Unit
The High-Hazards Unit is a regulatory body responsible for overseeing health and safety in high-risk industries, including quarrying. This unit conducts inspections, enforces compliance, and provides guidance to ensure worker and environmental safety.
Limestone
Limestone is a sedimentary rock primarily composed of calcium carbonate. It is extensively quarried for use in construction, agriculture, and industrial processes. Limestone is valued for its workability, durability, and chemical properties, making it suitable for diverse applications.
Load and Haul
Load and haul refers to the process of loading material onto off-road trucks or other transport vehicles and moving it to another location within the quarry, such as a crusher, stockpile, or processing plant. This operation is essential for the efficient movement of extracted materials. The equipment used for loading includes excavators and front-end loaders, while articulated dump trucks or rigid haulers are common for transportation. Effective load and haul operations rely on well-maintained haul roads and optimized vehicle routing to minimize fuel consumption and wear on machinery.
Load Out
Load out is the process of transferring processed materials from stockpiles onto road trucks for delivery to customers. Front-end loaders are typically used to load the material into the truck beds. This step often involves weighing the load to ensure compliance with legal weight limits and to provide accurate billing for the customer. Efficient load-out operations are crucial for maintaining customer satisfaction and reducing bottlenecks in the supply chain.
Managed Fill
Managed fill refers to fill material that is not classified as cleanfill but requires stricter management to ensure safety and compliance with environmental standards. This type of fill may include materials such as lightly contaminated soil or construction debris that does not pose significant environmental risks. Managed fill sites often require careful monitoring and record-keeping to meet regulatory requirements.
Manufactured Sand
Manufactured sand is a fine aggregate produced by crushing larger rocks into sand-sized particles, typically less than 5mm in size. It is used as a substitute for natural sand in concrete and asphalt production. Manufactured sand offers consistent quality and grading, and its use is increasingly encouraged in regions where natural sand resources are depleted or environmentally protected.
Moisture Content
Moisture content refers to the amount of water present in a material, expressed as a percentage of its dry weight. In aggregates, excessive moisture can impact compaction, mixing ratios, and overall performance in concrete or asphalt production.
Motorized Scrapers
Motorized scrapers are machines designed to quickly remove thin layers of material from the surface of a quarry or construction site. They consist of a bowl that can scrape and transport material to another location. These machines are particularly effective on firm ground and are used for site levelling, road base preparation, and other large-scale earthmoving tasks.
Noise Exposure Level
Noise exposure level refers to the amount of sound energy a worker is exposed to during a standard 8-hour workday. In quarrying, common sources of noise include blasting, crushing machinery, and vehicle engines. Regulatory standards typically limit noise exposure to 85 dB(A) over eight hours to prevent hearing damage. Noise-reduction measures, such as sound barriers, equipment modifications, and personal protective equipment (PPE), are implemented to protect workers.
Operator
In the context of quarrying, an operator can refer to the individual or company responsible for managing the overall operations of a quarry. Operators must ensure compliance with safety, environmental, and planning regulations. The term can also refer to skilled workers who operate machinery, such as excavators, loaders, or crushers.
Overburden
Overburden refers to the layer of soil, rock, or other material that lies above a deposit of minerals or aggregate. This material must be removed to access the underlying resource. Overburden is typically stored in designated areas within the quarry and may later be used for site rehabilitation or backfilling.
Particle Size Distribution / Grading Curve
Particle size distribution, represented by a grading curve, is a graph that shows the percentage of material passing through each sieve size in an aggregate sample. It provides a visual representation of the material’s gradation and is used to ensure compliance with specifications for concrete, asphalt, or other applications. Proper grading ensures the desired performance of construction materials.
Pavement
Pavement refers to the structure of a road, comprising multiple layers above the natural soil or subgrade. These layers typically include the subbase, basecourse, and surface layer. Pavements are designed to distribute traffic loads evenly and ensure durability under varying environmental conditions.
Permeability
Permeability measures the ability of a material to allow water to pass through it. Aggregates with high permeability are used in drainage layers, while those with low permeability are suitable for sealing applications.
Plasticity Index / Atterberg Limits
The plasticity index measures the plasticity of fine-grained materials, indicating the range of water content where the material exhibits plastic properties. It is determined through Atterberg Limits tests and is a critical parameter for evaluating the behaviour of soil and aggregate in construction projects.
Principal Hazard Management Plan (PHMP)
A PHMP is a comprehensive plan for managing principal hazards—those with the potential to cause multiple fatalities in a single event. In quarries, these hazards may include rockfalls, blasting incidents, or machinery accidents. The plan outlines risk assessments, control measures, and emergency response procedures to ensure worker safety and regulatory compliance.
Quarry
A quarry is an open-pit excavation site where materials such as stone, sand, gravel, or minerals are extracted. Quarrying operations include excavation, processing, and transportation of these materials for use in construction, infrastructure, and industrial applications. Quarries are often designed with multiple benches or levels to maximize resource recovery and maintain safety.
Regulations
Regulations in the quarrying industry encompass laws and standards designed to ensure safety, environmental protection, and operational efficiency. For example, the Health and Safety at Work (Mining Operations and Quarrying Operations) Regulations 2016 set out requirements for hazard management, worker training, and equipment maintenance.
Respirable Crystalline Silica (RCS)
Respirable crystalline silica refers to very fine silica particles, typically less than 2 microns in size, that can become airborne during quarrying and crushing operations. Prolonged inhalation of RCS can lead to serious health conditions, such as silicosis and lung cancer. Control measures include dust suppression, ventilation systems, and respiratory protective equipment.
Rippable Rock
Rippable rock is rock that can be loosened and excavated using mechanical equipment, such as a bulldozer, without the need for blasting. The rippability of rock depends on factors such as its hardness, density, and weathering.
Sand
Sand is a naturally occurring granular material with particle sizes ranging from 0.06mm to 2mm. It is often rich in quartz and used in various construction applications, including concrete production, mortar, and paving. Manufactured sand is increasingly used as an alternative to natural sand.
Sand Equivalent
The sand equivalent test measures the proportion of sand relative to silt and clay in an aggregate sample. A high sand equivalent value indicates a clean aggregate with minimal fine impurities, which is desirable for concrete and asphalt applications.
Scalping
Scalping is the process of separating undersized material from the feed of a crushing circuit. Scalping ensures that only material of the desired size range enters the crushers, improving efficiency and reducing wear on equipment.
Screening
Screening involves separating materials into different size fractions using vibrating screens or sieves. This process ensures that aggregates meet the specifications required for their intended applications, such as concrete, road base, or asphalt.
Sediment Control
Sediment control encompasses measures to prevent soil erosion and the discharge of sediment into water bodies. Techniques include sediment traps, settling ponds, and erosion control blankets, which are essential for minimizing environmental impacts during quarrying operations.
Settling Pond
A settling pond is a water reservoir designed to allow fine sediment to settle out of suspension. These ponds are commonly used in quarrying to treat process water and prevent sediment from entering natural waterways.
Shotfirer
A shotfirer is a trained and certified individual responsible for safely handling and detonating explosives during quarrying operations. Their role involves designing blasts, ensuring proper placement of charges, and timing detonations to achieve optimal rock fragmentation while minimizing fly-rock, vibration, and environmental impact. Shotfirers must adhere to strict safety protocols and regulatory guidelines to mitigate risks.
Silt
Silt refers to fine-grained sedimentary particles with sizes between 0.002 mm and 0.06 mm, smaller than sand but larger than clay. In quarrying, silt often accumulates in water management systems like settling ponds. Excessive silt content in aggregates can weaken concrete or asphalt, making its removal critical during processing.
Stripping
Stripping involves removing the overburden—soil, vegetation, and non-valuable rock—above a mineral deposit. This process is a prerequisite for accessing the resource beneath. Stripped material is typically stockpiled for future use in site rehabilitation or backfilling.
Sub-Base
The sub-base is an intermediary layer of aggregate placed between the subgrade (natural ground) and the basecourse in road construction. It serves as a foundation, distributing loads and providing drainage. Sub-bases often consist of well-graded materials to ensure compaction and stability.
Sub-Grade
The sub-grade is the uppermost layer of soil beneath a road or pavement structure. It supports all overlying layers and bears the transmitted loads from traffic. The quality of the sub-grade significantly impacts the longevity and performance of the pavement.
Subsoil
Subsoil refers to the layer of soil located immediately below the topsoil. It typically contains less organic matter and more minerals. Subsoil is removed or managed during excavation, particularly when its properties are unsuitable for supporting infrastructure.
Sump
A sump is a low-lying pit or reservoir within a quarry where water accumulates before being pumped out. Sumps are integral to water management, preventing flooding and ensuring operational continuity. Pumps used in sumps are often designed to handle sediment-laden water.
Topcourse
Topcourse is the uppermost layer of a road’s aggregate base, typically consisting of crushed rock with a nominal top size of 20 mm. It provides a smooth, load-bearing surface for lighter-duty roads or acts as a foundation for asphalt or concrete pavements.
Topsoil
Topsoil is the nutrient-rich upper layer of soil capable of supporting vegetation. During quarrying, topsoil is carefully stripped and stockpiled for future use in land rehabilitation or landscaping. Its preservation is critical for restoring ecosystems after quarrying operations cease.
Washing
Washing is a process used to clean aggregates by removing fine particles, dust, and other impurities. This is achieved through water sprays or specialized washing equipment. Washed aggregates are often required for high-specification applications, such as concrete and asphalt production, where cleanliness impacts material performance.
X-Ray Diffraction (XRD)
X-ray diffraction is an analytical technique used to determine the crystalline structure and mineral composition of aggregate samples. It is commonly employed in laboratories to identify clay minerals, which can affect the performance of construction materials. XRD results help in selecting suitable aggregates for specific engineering applications.
Yield
In quarrying, yield refers to the proportion of usable material extracted relative to the total amount of material removed, including overburden and waste. High yields indicate efficient operations, while low yields may necessitate operational adjustments or improved resource management.
Zone of Weakness
A zone of weakness is a natural fracture, fault, or discontinuity in the rock mass that can affect quarrying operations. These zones may lead to unexpected fly-rock during blasting or impact the stability of quarry faces. Proper geological surveys and monitoring help identify and manage these areas.
Zoning
Zoning refers to the designation of land use areas by local authorities. Quarries must operate within designated zones, which are determined based on factors such as environmental sensitivity, proximity to communities, and resource availability. Zoning approvals are often required before a quarry can commence operations.
