A trial of grazing beef cattle on rehabilitated mining land is showing encouraging results which point to a sustainable use of mined lands as commercially- productive pasture after mining has ended.
Halfway through the Upper Hunter Mining Dialogue’s Grazing Study, cattle grazed on rehabilitated pastures have been sent to market and tested; the cattle out- performed livestock pastured on nearby unmined paddocks which were used as analogue sites to compare results.
The study has now entered its second phase with new, larger herds of cattle introduced to the rehabilitated and analogue sites to comprehensively test the carrying capacity of the paddocks.
The Upper Hunter Mining Dialogue’s four-year grazing study started in June 2014 to evaluate how beef cattle would fare on rehabilitated mining land and whether the land would offer a commercially sustainable option for grazing livestock.
The trials see beef cattle grazed on rehabilitated land on Coal & Allied’s Hunter Valley Operations (HVO) mine site and BHP Billiton’s Mt Arthur Coal site. At the same time, cattle are grazed on analogue sites located nearby but on unmined land and results between rehabilitated and unmined paddocks are independently monitored and compared.
The study was designed and is monitored by the Department of Primary Industries in collaboration with the Upper Hunter Mining Dialogue Joint Working Group – Land Management, including representatives from agricultural groups, local farmers, environmental groups, state and local government and the mining industry.
The trial also monitors the health of the cattle through blood tests and monitors the pasture, providing valuable information on the growth rates and feed quality of the rehabilitated land.
With the study half-way completed, the first mobs of cattle have been sent to market with very encouraging results. In both trial sites, the livestock’s weight gain outperformed the cattle grazing on the analogue sites.
Cattle grazing on the HVO site were the big performers; at their final weigh-in the 10 steers that spent the past 18 months on the rehabilitated were found to be 150 kilograms heavier on average than cattle grazed on unmined farming land.
Importantly, tests performed on the carcasses after slaughter have shown no unusual results due to the pastures formerly being used for mining.
Ongoing study: As the study enters its second stage, herds of weaner steers have been recently introduced to the rehab and analogue sites to continue gathering data over a range of seasonal conditions and comprehensively test the carrying capacity of the paddocks.