Dust Suppression for Stockpiles, ROM Pads, Hardstands and Processing Areas

Haul road dust suppression receives the most attention on mine sites — and for good reason. Haul trucks generate the majority of fugitive dust emissions, accounting for 78–97% of total particulate matter at surface operations. But the remaining 3–22% is not trivial. It comes from stockpiles exposed to wind erosion, ROM pads where material is dumped and reclaimed, crusher and conveyor transfer points where material is processed, hardstands and laydown areas where heavy equipment operates, and exposed surfaces such as bunds, batters and cleared land.

Each of these sources generates dust through different physical mechanisms, presents different operational constraints, and requires different suppression strategies. A site that achieves excellent haul road dust control but neglects these other sources will still fail regulatory monitoring at the site boundary, still expose workers in processing and stockpile areas to hazardous particulate, and still generate community complaints from wind-blown dust off untreated surfaces.

This article examines the major non-haul-road dust sources on a mining operation, the specific mechanisms by which each generates airborne particulate, and the engineering controls appropriate to each. The objective is a total site dust management approach that addresses every significant source, not just the most visible one.

Ore and Coal Stockpiles: Wind Erosion, Material Loss and Combustion Risk

Stockpiles are among the largest exposed surface areas on a mine site and among the most problematic dust sources. The dust generation mechanisms are distinct from traffic-generated dust: the primary driver is wind erosion of the exposed surface, combined with mechanical disturbance during stacking and reclaiming operations.

The propensity of a stockpile to generate dust depends on the material type, particle size distribution, surface moisture content, stockpile geometry (flat-topped piles emit less dust than conical ones), local wind velocity, and whether the surface has formed a natural crust or remains loose. Coal and coke stockpiles are particularly problematic, generating more airborne dust than equivalent stockpiles of limestone, iron ore or bauxite due to the lower specific gravity of coal particles and the hydrophobic nature of coal surfaces that resist wetting.

The consequences extend beyond air quality. Wind erosion of ore stockpiles represents a direct loss of material that has already been mined, hauled and processed to that point — a loss of economic value. Water run-off from rain contaminates groundwater and local waterways with suspended solids and, in the case of metalliferous ores, dissolved metals. And for coal stockpiles, the additional hazard of spontaneous combustion must be managed: wind accelerates the low-temperature oxidation that causes self-heating, and effective dust control that reduces air ingress into the stockpile surface also reduces combustion risk.

Engineering Controls for Stockpiles

Effective stockpile dust control requires a surface treatment that creates a wind-resistant veneer on the exposed surface without interfering with material reclamation or altering product quality. Water-only spraying is inadequate for all but the most temporary applications: it evaporates rapidly from the large exposed surface area, provides no residual protection, and on coal stockpiles may not wet the surface effectively due to the hydrophobic nature of coal.

GRT: Ore-Loc is a polymer-based liquid veneering solution designed specifically for this application. Applied to the stockpile surface using water trucks or bespoke spray bar systems, the polymer fuses fine particles on the surface into a thin, bonded, erosion-resistant crust. This crust resists wind erosion at velocities that would strip unprotected surfaces, prevents material loss during storage, and reduces rain-driven sediment run-off. Critically, the veneer does not alter the properties of the underlying material — it can be reclaimed normally, with the treated surface layer representing a negligible fraction of total stockpile volume.

For coal stockpiles, GRT: Activate UG addresses the specific challenge of coal’s hydrophobic surface chemistry. As an ionically charged product, it lowers the surface energy barrier that prevents plain water from effectively wetting coal particles. The result is that the activated water binds even the finest coal dust particles, stripping hazardous respirable dust from the air during stacking and reclamation operations. Importantly, it does not alter the burning properties or commercial quality of the coal.

ROM Pads: The Intersection of Dust, Traffic and Material Handling

Run-of-mine pads are high-activity zones where material is dumped from haul trucks, temporarily stored, and reclaimed by front-end loaders or feeders for crushing. They combine the worst characteristics of multiple dust sources: heavy vehicle traffic on an unpaved surface (similar to haul roads), material dumping that releases a plume of fine particulate on impact, loader operations that mechanically disturb stored material, and wind erosion of the exposed stockpile face.

ROM pads are also typically located adjacent to the primary crusher, placing them in close proximity to workers operating fixed and mobile plant. The dust generated at the ROM pad contributes directly to personal exposure levels for loader operators, crusher attendants, and any personnel working in or transiting through the area.

The suppression strategy for a ROM pad must account for the fact that the surface is continuously disturbed. Unlike a haul road where the surface is trafficked but not excavated, a ROM pad surface is regularly ripped up by loader buckets, re-graded, and covered with new material. Long-duration surface treatments are impractical for the active tipping and reclaiming areas; instead, the focus shifts to suppressing dust at the point of generation — during dumping, during loading, and during wind events — using spray systems with suppressant-dosed water.

GRT: Activate is engineered for this dynamic environment. Dispensed through existing spray systems, water trucks or stabilisers, it makes water work more effectively by modifying its surface tension and charge characteristics to attract and capture fine dust particles on contact. For the static areas of the ROM pad — the surfaces not actively being worked — a combination of Haul-Loc for trafficked surfaces and Ore-Loc for exposed stockpile faces provides layered protection.

Hardstands, Workshops and Heavy Equipment Yards

Mine site hardstands — workshop surrounds, heavy vehicle parking areas, pipe laydowns, container yards, fuel bays and logistics staging areas — generate dust from a combination of vehicle traffic and wind erosion. These areas are typically constructed from compacted gravel or crushed rock and are subject to traffic from a mix of haul trucks, service vehicles, forklifts, cranes and tracked equipment.

The challenge with hardstands is durability under diverse traffic types. Tracked equipment (dozers, excavators) is particularly destructive to surface treatments that form a brittle crust, as the tracks shear and break the surface layer. Water-based treatments evaporate quickly on exposed, well-drained hardstand surfaces. And many hardstand areas are located near workshops, fuel storage and accommodation where dust has a direct impact on equipment maintenance costs, worker amenity and community perception.

GRT: Wet-Loc is specifically formulated for these high-traffic, mechanically demanding environments. As a non-drying, non-setting synthetic fluid, it works by adsorbing into soil particles and weighing them down — like water, but without evaporation or freezing. The non-film-forming formulation means it is not damaged by tracked equipment, chained wheels or heavy shear loads. Applied neat (without water), it provides dust control for 4–12 months depending on traffic intensity, and requires no cure time — the treated area is ready for vehicle traffic immediately after application.

For operations where water-based systems are impractical — such as areas near electrical infrastructure, underground access portals, or locations where water run-off must be strictly controlled — Wet-Loc’s waterless application method eliminates these constraints entirely.

Crushers, Conveyors and Material Transfer Points

Material processing infrastructure — primary and secondary crushers, conveyor transfer points, screen houses, bins and feeders — generates dust through the mechanical fracture and displacement of material. Every time rock is crushed, screened or transferred between conveyors, a proportion of the fine fraction becomes airborne. The dust generated at these points is typically high in respirable crystalline silica (in hard rock operations) or combustible coal dust, making it both a health hazard and, in coal operations, an explosion risk.

Enclosure and extraction systems (baghouses, wet scrubbers, dust collection hoods) are the primary engineering controls for fixed processing plant. However, these systems require supplementary suppression at the point of generation — particularly at open crusher feeds, conveyor discharge points, and transfer chutes where enclosure is incomplete or impractical.

GRT: Activate is designed to be injected through existing spray systems at these processing points. By modifying the water’s surface tension and ionic charge, it ensures that the spray droplets attract and bind fine dust particles rather than simply wetting the larger material fraction. Independent testing has verified that GRT’s activated water technology is 12 times more effective than water alone in suppressing coal dust and other fine particulate — a critical performance differential in applications where respirable dust is the primary health hazard.

Bunds, Batters, Cleared Land and Decommissioned Areas

Every mine site has large areas of exposed, unvegetated surface that are not actively trafficked or worked but are nonetheless significant dust sources. These include perimeter bunds, waste dump batters, topsoil stockpiles, cleared construction footprints, and decommissioned operational areas awaiting rehabilitation. In aggregate, these surfaces can represent tens or hundreds of hectares of exposed ground.

Wind erosion from these surfaces is the primary mechanism. Unlike haul roads or ROM pads, where dust generation is driven by vehicle activity, these areas generate dust passively — whenever wind speeds exceed the threshold velocity for the surface material. This makes them particularly problematic during high-wind events, when they can generate dust plumes that exceed site boundary monitoring limits regardless of how well the active operational areas are controlled.

GRT: Soil-Loc is designed for long-term dust suppression on these large, static surfaces. Applied from a water cart or cannon, the polymer binds exposed soil particles into a wind-resistant surface layer that persists for months without reapplication. For erosion-prone batters and stockpile slopes, GRT: Enviro-Binder provides polymer-based surface stabilisation that resists both wind erosion and water erosion from rainfall events — protecting exposed surfaces while rehabilitation vegetation establishes.

Total Site Dust Management: Matching Products to Sources

GRT product selection by dust source and application

The table above illustrates the principle that no single product addresses every dust source on a mine site. Each source has different physical characteristics, different operational constraints and different treatment requirements. A total site dust management strategy selects the appropriate product for each source, integrates the delivery systems, and coordinates application schedules to maintain site-wide compliance.

Regulatory and Community Context

Australian mining dust regulations are assessed at the site boundary, not at individual dust sources. This means that a site with excellent haul road dust control but uncontrolled stockpile or batter erosion can still exceed PM10 limits at downwind monitoring stations during adverse weather conditions. Environmental authorities in Queensland and New South Wales assess compliance based on total site emissions, and the trend is toward more stringent monitoring — with proposed reductions in the national workplace exposure standard for respirable crystalline silica from 0.05 to 0.025 mg/m³.

Community complaints follow the same pattern. Wind-blown dust from stockpiles and exposed surfaces can travel kilometres, affecting residential areas, agricultural properties and sensitive environmental receptors well beyond the mine boundary. The social licence implications of visible dust plumes from uncontrolled stockpiles or batters can be more operationally disruptive than the dust itself — generating regulatory scrutiny, media attention and conditions on future approvals.

A total site approach that addresses every significant dust source — not just the haul roads — is the only strategy that reliably delivers site boundary compliance and community acceptance across all weather and operational conditions.

From Haul Road to Site Boundary: The Complete Picture

Haul road dust suppression is necessary but not sufficient for total site dust management. The stockpiles, ROM pads, hardstands, processing areas and exposed surfaces that surround the haul road network each generate dust through distinct mechanisms and each require purpose-designed engineering controls. Treating them all with the same water truck and hoping for the best is not a strategy — it is a gap.

The engineering approach is to map the dust sources, characterise the generation mechanism at each, select the appropriate suppression technology, and integrate the delivery and monitoring systems into a coherent, site-wide programme. The products exist. The delivery systems exist. The monitoring technology to verify performance exists. What is required is the decision to treat dust management as a whole-of-site engineering discipline rather than a collection of independent, reactive interventions.

For mining engineers and environmental managers responsible for site-wide air quality, the first step is an honest assessment: which sources on your site are controlled, which are partially controlled, and which are generating dust that reaches the boundary unmitigated? The answer to that question defines the scope of work needed to achieve genuine total site dust management.

Sources and References

Kung, H.C. et al. (2024): Techniques for Suppressing Mineral Dust Aerosol from Raw Material Stockpiles and Open Pit Mines: A Review. Aerosol and Air Quality Research, 24.

Cole & Zapert (1995); Reed et al. (2001): Haul trucks generate 78–97% of total PM emissions at surface mines. Referenced in NIOSH and EPA literature.

Mining Technology: Global Road Technology — company and product overview