BHP has for more than a decade set OELs for our most material exposures based upon the latest scientific evidence, which for a number of agents resulted in stricter levels than the then regulatory requirements, and for others, such as DPM, a significantly lower limit than regulations require. Where exposures potentially exceed regulatory limits or the stricter BHP limits, respiratory protective equipment is worn.
In addition, for our three most material exposures to DPM, silica and coal mine dust, we have a five-year target to achieve a 50 per cent reduction in the number of workers potentially exposed(1) as compared to our baseline exposure profile (as at 30 June 2017(2)(3)) by 30 June 2022.
In FY2016, we committed to applying an OEL of 0.03 mg/m3 for DPM and in FY2017 we committed to applying OELs of 1.5 mg/m3 for respirable coal mine dust by 1 July 2020 and 0.05 mg/m3 for silica by 1 July 2021. Exposure data reported here is based on these limits and in all cases discounts the use of personal protective equipment.
In FY2020, there was a reduction in the number of workers potentially exposed to silica at a level in excess of our OEL of 8 per cent compared to FY2019 reported by our Minerals Americas operated assets. An initial qualitative assessment of some work groups indicated potential exposure in excess of our OEL; however, an extensive quantitative assessment determined exposure to be less than estimated and less than our OEL. At our Minerals Australia coal operated assets, implemented exposure reduction projects have reduced the number of workers potentially exposed to silica at a level exceeding our OEL in FY2020 by 30 per cent compared to FY2019. Overall, in FY2020 we achieved a reduction of 13 per cent compared to FY2019 in the number of workers potentially exposed to silica in excess of our OEL.
In FY2020, potential exposure to respirable coal mine dust remained below our OEL in all operated assets. At Olympic Dam, ongoing work has continued to refine diesel exhaust emission controls, while at Nickel West, work has been undertaken to improve the maintenance and operation of the ventilation system which, coupled with changes to the underground vehicle fleet, has resulted in a further reduction in the number of workers potentially exposed to DPM in excess of our OEL. Potential exposure has reduced by 55 per cent compared to FY2019 and by 88 per cent compared to the adjusted FY2017 baseline. Overall, our material exposures to DPM, silica and coal mine dust have reduced by 60 per cent compared to the adjusted FY2017 baseline, which exceeds our FY2022 target.
Training on health hazards is provided in inductions at hire and periodically thereafter. Workers who use hearing and respiratory protective devices are provided with information on health exposures and training when they are fit tested for those devices. Where workers take part in occupational exposure assessment programs, they receive written feedback on their results and de-identified data is provided to line management.
We are progressing a project to enable real-time monitoring of silica and DPM. While not yet embedded in the business, successful trials of instruments have been conducted across Minerals Australia and Minerals Americas operated assets. Fixed-position monitors can identify dusty conditions in real time, enabling controls such as increased ventilation or water sprays to be deployed. Data from personal monitors is available at the end of shifts rather than weeks later, when results of samples sent to the laboratory for analysis become available. This enables prompt action to be taken if potential exposure increases or exceeds our OEL.
In Minerals Australia, a project was undertaken to control silica exposure of blast crew workers who prepare blast holes. Holes must be filled or stemmed with material before being blasted. The stemming material and wind-blown dust from the surrounding area were found to be the sources of silica. A number of potential stemming materials were examined and a coarser material selected which had been carefully sized to contain very low amounts of fine (potentially respirable) material. A dedicated water cart is available to wet the area down prior to work, greatly reducing the amount of wind-blown dust.
At our NSW Energy Coal operated asset, compressed air had traditionally been used to clean an electrical control box in ultra-class trucks, potentially exposing operators to silica dust. The compressed air was replaced with high-efficiency vacuum cleaners and the control box pressurised, minimising silica exposure and reducing the frequency of cleaning.
In Minerals Americas, silica-exposure reduction projects were implemented at Escondida and Pampa Norte operated assets in Chile. This included the construction of a second dust collector on Line 2 of the dry area of the plant to extract dust from tunnels and conveyor belts and the use of binder on transfers points and stockpiles in the dry areas. At Cerro Colorado (a part of Pampa Norte), a process was implemented to remove dust collected on screens and the secondary and tertiary crushers prior to maintenance.
At the Broadmeadow mine (a part of our Queensland Coal operated assets) we commenced replacing engines on heavy diesel equipment which is used on long wall moves. The new engines are supercharged and have modified exhaust conditioning, with the combined effect enabling engines that produce the same power but about 75 per cent less DPM. A long wall is a machine used to cut coal in an underground mine that periodically must be dismantled and moved to a different part of the mine. This is an intensive process involving a number of heavy machines.
We reported in FY2019 on work being undertaken to develop electric vehicles for use in underground coal mines. In FY2020, development has continued, and we now have a nine-seat people carrier approved for use underground with two more under construction. Vehicles in underground coal mines must be electrically certified, which means they cannot produce sparks or be the source of fire. A standard vehicle requires modified brakes, gas detection and additional safety circuits to limit temperatures to sub 150oC, and batteries must be protected. Additionally, we are working with equipment manufacturers to develop an electric 10-tonne heavy vehicle which would be the forerunner of a diesel-equipment-free mine, eliminating potential exposure to DPM and exhaust gasses during normal operation.
Coal mine dust lung disease
In our Sustainability Report for FY2017, we reported on the re-identification of coal workers’ pneumoconiosis (CWP) in our industry, the number of our current employees and former workers who had been diagnosed with CWP and the steps we had taken in response. We have updated this information in our reporting for each subsequent financial year.
As at 30 June 2020, two cases of coal mine dust lung disease (CMDLD)(4) were recorded among our current employees at our coal operated assets. In addition, one current employee who had previously been recorded as a case of CMDLD had a workers’ compensation claim accepted. There were five former BHP employees who had a workers’ compensation claim accepted for CMDLD in FY2020.
We have implemented controls at all our operated assets with the goal that none of our workers be exposed to respirable coal mine dust in excess of our OEL. We continue to be vigilant with projects such as real-time dust monitoring to ensure exposures remain controlled.
To seek to strengthen the regulatory framework and health surveillance system, we will continue to provide input and share improvements in technical knowledge and controls with the Queensland Government and the coal mining industry more broadly through industry associations and working groups.
1. For exposures exceeding our FY2017 occupational exposure limits discounting the use of personal protective equipment, where required.
2. The baseline exposure profile is derived through a combination of quantitative exposure measurements and qualitative assessments undertaken by specialist occupational hygienists consistent with best practice as defined by the American Industrial Hygiene Association.
3. The baseline has been adjusted to exclude Discontinued operations (Onshore US assets).
4.CMDLD is the name given to the lung diseases related to exposure to coal mine dust and includes coal workers’ pneumoconiosis, silicosis, mixed dust pneumoconiosis and chronic obstructive pulmonary disease.