Cautioning that dumping of fly ash into mine voids may be contaminating the groundwater, an expert panel of the Union environment ministry proposed recently “a detailed research” for at least a decade
Cautioning that dumping of fly ash into mine voids may be contaminating the groundwater, an expert panel of the Union environment ministry proposed recently “a detailed research” for at least a decade to address the brewing problem. The expert appraisal committee (EAC), in its final minutes of the meetings, also pointed out that fly ash pits in coalmines could cause “uprooting of trees” due to it being non-conducive to their “root system development”.
So far, there is no conclusive evidence on whether disposal of fly ash in mine voids, which is a common practice, causes any environmental degradation even though concerns over the same are now being raised. An estimate of 90 million tonnes of the fly ash, which is caused due to combustion of coal, is generated annually in India, of about only 50-60 per cent is utilised.
The National Green Tribunal (NGT) in 2015 had directed the Central Pollution Control Board (CPCB) to check if any damage has been incurred to mine pits in Orissa where the disposal of the toxic ash is rampant.
The EAC meeting for thermal power and coal mining projects held on February 29 suggested that in the research, which necessitates from ambiguity on fly ash’s affect to the environment, the assistance of corporate companies engaged in generating power using coal can be sought.
“The infiltration of rain water falling on fly ash filled mine void is confined only to the top 1 m or even less, and as such there will be reduction in recharging of ground water in the area,” the committee noted, adding, “The interface between the water and fly ash at the bottom of such voids results in leaching of heavy metals into ground water system as evident by high levels of trace elements in ground water samples collected from sites located close to the ash filled voids.”
It also came to notice, the expert panel said, that “at the bottom of constructed fly ash dyke (void), the ash was found floating leading to the collapse of the entire pit at a Nalco plant in Talcher in Orissa.
On affect of ash filled voids on trees, the panel observed: “The ash filled voids cannot support the tree species because of poor root system development which in turn results in uprooting of trees even by low velocity winds.”
Pointing out the vulnerability of such disposal mechanisms even in the US, the panel argued that even the lining system for mine voids, which has not been worked out in India yet, have not proven to be completely successful as is evident from leaks of heavy metals into ground water system reported from the United States.
Therefore, the committee headed by chairman EAC, Anil Kumar exhorted: “a detailed well-planned, multidisciplinary, long-term (at least 10 years) research is urgently needed to address the problems of fly ash disposal into mine voids. MoEFCC is requested to take necessary action to launch the programme under environment research division.”
