Road dust.
With the plethora of environmental concerns that we face today, the trouble with road dust can often be overlooked. However, despite its innocuous appearance, the dangers of road dust are very real for people who live in areas with a higher proportion of unpaved surfaces. In fact, according to the US Federal Highway Administration (FHWA), as much as 35% of the 4 million miles (or 6.4 kilometres) of roadways in the United States are classified as rural with many being unpaved gravel roadways. It has been reported that these unpaved roads are responsible for more than 10 million tons of particulate matter emissions each year in the United States!
Within the mining industry, the prevalence of road dust is even higher. In addition to the high volume of traffic on the mine sites, the very activities that sustain mining operations – blasting, drilling, hauling – contribute to the generation of copious amounts of dust. Fine particles, ranging from respirable dust (PM2.5) to coarse particulate matter, become airborne as vehicles traverse unpaved roads posing respiratory hazards to workers and nearby communities.
What are the effects of road dust?
While brief exposures to road dust will pose little harm, ongoing and relentless exposure to road dust can have lasting and harmful impact. When discussing the amount of dust generated at mine sites from blasting, drilling and hauling activities, one can imagine that we are not dealing with inconsequential amounts!
Health Hazards
Road dust is composed of fine particles suspended in the air. As vehicles and traffic traverse road surfaces, they gradually wear down asphalt, concrete, and tires. The impact is amplified on unpaved gravel road surfaces. Particles larger than 2.5 microns can lodge in the upper respiratory area where they may cause severe irritation, even linking to respiratory cancer in some cases. Particles that are smaller than 2.5 microns can go even deeper into the lungs where they can cause damage to the epithelial cells or pass into the blood stream. A recent study by the Miami University in Ohio determined that metal pollution can remain pervasive in road sediment, even years after industrial activity. The study found legacy waste from industrial activity as well as lead from leaded gas and paints and dangerous pollutants like hexavalent chromium, thought to be released from aging yellow traffic paint in road sediments.
These dangerous pollutants in road sediment and road dust can lead to chronic health issues. Lead exposure can cause neurological and development issues while overexposure to manganese can lead to neurological toxicity. Overexposure to hexavalent chromium (a human carcinogen) can lead to an increased risk of asthma, renal damage, cancer and negative effects on reproduction. Prolonged exposure to any dust can cause irritation to eyes, skin and respiratory tract, lung disease including silicosis, coal workers’ pneumoconiosis, chronic obstructive pulmonary disease and lung cancer.
Environmental Impact
Of course, wildlife and animals are not immune to these health impacts not to mention the impact on the surrounding environment and ecosystems. As noted in this NCBI article, dust impacts not only the air but the water as well as dust particles can settle on nearby streams and rivers. Water clarity can decline which will have a lasting and dangerous impact on the wildlife and plant life that depend on the water source. Studies have shown that dust on leaf surfaces increases leaf temperatures and water loss while also decreasing carbon dioxide uptake. This can lead to chronic decreases in photosynthesis and growth, eventually leading to erosion from lack of adequate stabilizing vegetation.
What are the issues with dust in mining?
Cypher’s DUST/BLOKR being applied for long term dust control on haul road.
Beyond the public health and environmental concerns listed above, the massive volumes of dust produced by mining activities can cause unsafe driving conditions by reducing visibility and increase wear and tear on equipment, machinery and infrastructure. Coal dust is also an important cause of underground explosions.
How do you control dust in mining operations?
Addressing the challenge of mining road dust requires a comprehensive approach that takes into account protected areas or vulnerable species nearby, equipment availability and regulatory oversight. Implementation of water trucks, dust suppressants and vegetative buffers can aid in the mitigation of suspension of dust particles in the air. As noted in the NCBI article, “Down with Road Dust”, there are a number of dust suppressants that are available.
Traditional dust suppressants generally fall into one of six generic categories: surfactants, which are short-term wetting agents requiring frequent application; adhesives such as lignin sulfonate (tree sap), which act as binders to form a seal over the surface; electrochemical stabilizers derived from sulfonated petroleum, which expel water from the soil and increase compaction; petroleum products, which bind fine particles together; chloride salts, which both attract moisture from the atmosphere and retard its evaporation; and miscellaneous other products including microbiological binders and polymers.
While each of these solutions can be effective in controlling dust, some of these products pose environmental hazards that are worse than the dust itself! A recent study has found that “no matter what suppressant was used, [you] would see some sort of water quality impact. Some compounds like the petroleum compounds, contributed more metals, volatile organic compounds, and the like, while others, like magnesium chloride, had a less noticeable environmental impact.”
An Environmental Dust Control Solution
Given the public health and environmental concerns of road dust and the harmful impact of some traditional dust suppression solutions and the heightened concerns of the global climate crisis, Cypher Environmental set out to develop an alternative dust suppression solution that could achieve superior dust control results without harming the environment. Cypher’s DUST/BLOKR® is a groundbreaking alternative to traditional road salts. It offers a superior dust control solution that is non-corrosive, non-toxic, organic and bio-degradable without compromising the environment.
DUST/BLOKR’s unique formulation works by improving the road’s engineering properties and weatherproofing the road surfaces for both wet and dry conditions. DUST/BLOKR increases water resistance by helping shed water, resulting in a more stable road in wet conditions that does not get slippery.
DUST/BLOKR products are seasonal dust control solutions that are designed to reduce the frequency of treatments. Mining clients have found their usage of water and fuel consumption (from watering trucks) to have drastically reduced after incorporating DUST/BLOKR into their operation. The Shenhua Beidian Shengli Open Pit Coal Mine in Inner Mongolia reported an impressive 85% reduction in water consumption.
Resources:
“Down with Road Dust”, National Center for Biotechnology Information (NCBI) Volume 111 Number 16, December 2003
“Road Dust: A Health Hazard Hidden in Plain Sight“, Eos, November 7, 2019