Proximate geographical locations of farming activities to mining activities raise a cause for concern with regards to airborne dust that is generated at mines and how it pollutes the environment to the extent of compromising food security. Upfront, it should be also be noted that farming activity itself can generate significant dust as well as wind and water erosion issues, however, this significant issue is not our primary focus in this article. Forecasted projections from the Queensland agriculture and food production for the season 2017-2018 show that Queensland consists of 34% of Australia’s total farm area, whilst growing 94% of the nation’s sugarcane, 34% of the nation’s cotton, 33% of grains and 30% of vegetables. According to the Australian Bureau of Statistics 2018-2019, Central Queensland’s agricultural sector is dominated by cattle and calves, followed by cotton, pulses, wheat, sorghum and other commodities. Coal mining regional communities in Central Queensland include Moranbah and Mackay. The air quality of these regional communities is vastly affected by mining operations given that both Moranbah and Mackay sit in the Queensland’s Bowen Basin coalfields which represent 85% of the Queensland coal industry. PM concentrations of coal dust are significantly higher in Moranbah and Mackay because of their proximity to coal operations. Coal dust can be transported rapidly and over long distances. This article seeks to highlight where coal mining specifically meets farming in the context of dust control in Australia, unpacking the air quality debacle and its effects on agricultural productivity and summed up with viable solutions for controlling coal dust at the source.
How does dust impact farming?
Air pollution and specifically dust affect agriculture with the potential to reduce both the yield and nutritional quality of crop plants. It affects plants by either reducing yields or degrading the quality of agricultural product. Presence of high levels of suspended particulate matter is a huge problem for agriculture, with examples of coal dust that deposits on plants affecting their nutrients, photosynthesis and production. Sulphur in coal dust affects respiration of crops and on reaction with dew and rainwater, it produces an acidic compound that burns up crop lamina and reduces crop outputs. Coal dust is chemically reactive given its chemistry which is attributed to elements, functional groups and free radicals. Blocked stomata and leaf injury is common in commercial crop species leading to an overall reduction in vegetative growth and reproductive structures. The effect of chemically reactive dust can lead to the irregular distribution of chloroplasts and complete seizure in starch formation which can lead to secondary effects such as pest infestations and fungal infections. Effects of coal dust may be experienced through changes in soil chemistry which may have a long term effect on crops.
Where is coal dust generated?
Coal mining operations generate dust from excavating, crushing, grinding, separation, refining, stockpiling for coal reject dumps, conveyor systems, haulage and veneering amongst many other processes that take place at mines. Open-pit coal mine operations generate a substantial amount of dust and other particles into the atmosphere. Towns within the vicinity of coal mine operations tend to bear the brunt of coal dust generated from these mining activities but in the discussion at hand, we evaluate the effect of coal dust on agricultural production. The mechanisms of deposition of coal dust on agricultural produce solely depends on the diversity of the plant organs which includes foliage, branches and bole surfaces which interact differently based on the area of deposition. For example, some deciduous species are likely to remove particulate matter even when they are leafless in winter owing to stem structures. Research has shown that deposition on leaves tends to weaken plant photosynthesis as result of obstruction to the stomata which leads to stunted plant growth. In general tree barks have shown greater tolerance to pollutants over the years therefore effect of coal dust on different vegetative organs play a role in overall effects of coal dust on agricultural production.
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Industry example – impacts on livestock
The largest contributor to the Central Queensland agricultural sector is livestock production. The approach to the effect of coal dust on livestock production is related to reduction in grazing capacities as a result of the vegetative effects of coal dust mentioned above. In most cases, livestock production is combined with crop production where natural and cultivated pastures provide grazing in summertime and combined maize fields provide grazing in wintertime. Following the recurring problems of coal dust in Moranbah, persistent resident complaints and farming community losses in agricultural production pushed the Queensland Government to introduced the Recognised Standard 20 in 2019 which falls under section 37(3) of the Coal Mining Safety and Health Act 1999 for the purposes of tackling dust control in surface mines. In principle, Recognised Standard 20 is a standard that was made for safety and health stating ways to achieve an acceptable level of risk to a person arising out of coal mining operations. The imperative is to identify sources of dust generation in all areas of the surface mine and develop and implement dust controls for each activity at a surface mine on both a short term and long term scale in the interest of managing dust control. Preferably the most effective way in the hierarchy of controls is the elimination of coal dust at the source before exposure can occur.
Understanding coal chemistry is the key
Coal chemistry has been researched at length and its implications on the choice of dust control solution strongly determines the efficacy of the selected dust control measures. The aftermath of the failure to control coal dust at the source has negative and costly repercussions on agricultural production. Effective methods of dust control improve air quality in the areas within the vicinity of coal mine operations and most importantly in the context of our discussion improves and maintains agricultural production without deleterious effects on vegetative organs. Global Road Technology offers coal dust control solutions that factor in the chemistry of coal, particle size and longevity of dust control which all feeds into the apex of the hierarchy of control as stated in Recognised Standard 20 with an intention to completely eliminate coal dust at its source, as well as options for all operations pit to port such as GRT: Haul-Loc, GRT: Wet-Loc and GRT7000. Coal dust control is ineffectively controlled by using water alone as the chemistry of water is poorly compatible with the coal as it is predominantly hydrophobic (water-hating). In order to make water work, Global Road Technology recommends their coal specific products, GRT Activate and GRT Activate UG which super activates water. The amphiphilic nature of GRT Activate and GRT Activate UG enable dual interaction as both hydrophobic and hydrophilic in the process making water work and achieving effective coal dust suppression at the source. Therefore, coal mining meets farming in the case of achieving dust control at the source which in Australia as given for Central Queensland the synergy in dust control at the source offers better air quality which is beneficial to agricultural production.
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REFERENCES
Farmer, A.M. 1991. The effects of dust on vegetation- A Review. Environmental Pollution. 79. 63-75.
