How Green Was My Valley – Part I
Co-Written by Ranjana Padhi & Lambodar Mohanto
An overview of chromite mining in Sukinda valley in Odisha
It is no mere exaggeration to say that almost the entire of chromite resources in the country is located in Odisha. The major share of chromite deposits (98.6%) associated with ultramafic[i] complexes are in Sukinda and Baula Nuasahi region.
The Sukinda ultramafic complex (Longitude: 85° 40′ E -85° 52′ E and Latitude: 20° 40′ N- 20° 57’N) has nearly 95% of the total chromite reserves of the country. This area is part of Jajpur district and lies between village Kansha in the east and village Marubil in the west.
The Sukinda ultramafic field is confined to an east-west trending valley lying between the Daitari hill range in the north and the Mahagiri range in the south. The area has a width of 2 to 5 km and extends for a length of nearly 25 km in an ENE-WSW direction from Kansa in the east to Maruabil and beyond in the west.
The history of chromite exploration in Sukinda valley started way back in 1949. Curiously, some boulders of chrome ore were reported by a local tribal named Kate Purty. Soon after, the occurrence of chromite in the valley was brought to light by the geological wing of Tata Steel.
The area has around 12-14 mines. Those in operation are:
- Odisha Mining Corporation (OMC) (South Kaliapani)
- Sukinda Chromite Mine TISCO
- Ferro Alloys Corporation FACOR (Ostapal Mines)
- Mishrilal Mining Pvt Ltd
- B C Mohanty and Sons
- Mahagiri Chromite Mines (IMFA)
- Balasore Alloys Ltd (Kaliapani)
These mines use the opencast mining methods for extraction of chromite ore. It is well known that opencast chromite mining generates huge volumes of seepage water. This water seeps into the ground of the quarry. It dissolves the chromium. The chromium in trivalent stage Cr(III) turns into the hexavalent Cr(VI) form due to complex reactions (including oxidation). Hexavalent chromium is more soluble in water than any other form. It is also the most toxic form of chromium. Studies have shown that Cr(III) in minerals can get oxidised to Cr(VI) and its problems are aplenty. When Cr(VI) in mine drainage water is released (untreated) it contaminates all water bodies – surface water as well as ground water.
In Sukinda, the chromite ore and waste rock material are dumped in the open without any consideration of its impact on the environment. Leaching of heavy metals takes place in the rainy season that becomes a source of pollution for both ground water and surface water bodies. The ultramafic rocks in the area get heavily weathered and metamorphose at places giving the laterite soil, in turn, a cover up to a depth of more than 20 metres. Extensive mining of chromite in the area since several areas poses serious threats to the environment through pollution of toxic hexavalent chromium in soil and water bodies.[ii] Water naturally occurring and discharged from mine quarries due to excavation is also invariably contaminated with Cr(VI) and other heavy metal ions which are usually discharged into the surrounding environment. In addition to the accumulated seepage, water in the chromite mine quarries of Sukinda is evacuated by pumping that ultimately finds its way into the stream water of Damsala Nalla, the principal drainage channel of the valley.
Chromium hexavalent is mobile in the environment and is highly toxic to all forms of living systems including microorganisms which cause oxidative stress in organisms. It can easily penetrate the cell wall and all biological membranes. Moreover, chromium hexavalent is also mutagenic, carcinogenic, and teratogenic and has been recognized as a priority pollutant.
In the year 2007, the US-based Blacksmith Institute released a report taking a range of parameters to identify the ten most polluted places in the world. India had two such places; Sukinda was one of them. Considering the fact that Odisha accounts for almost the entire source of chromite ore reserves, these mines in Sukinda valley generate considerable quantity of pollutants containing toxic hexavalent chromium, a known carcinogen, which contaminates 10~4000 mg/kg(ppm) of total chromium in air, water and soil environment. Surface water and ground water in Sukinda region contain hexavalent chromium well above the permissible limits of 0.05 mg/l (ppm).
The unsafe chromium pollution produces adverse health effects in people in the vicinity who are exposed to it. They suffer from a range of diseases, such as ulcers, allergies, brain damage, premature deaths and liver and kidney ailments. Chromium toxicity is known to have effects on the skin, nose, lungs, kidney, liver, brain, gastrointestinal tract and mutagenicity of human organs. The Odisha Voluntary Health Association (OVHA) reported that 84.75% of deaths in the mining areas and 86.42% of deaths in the nearby industrial villages occurred due to chromite mine-related diseases. The survey report determined that villages less than 1 km from the sites were the worst affected, with 24.47% of the inhabitants found to be suffering from pollution-induced diseases.[iii]
The drainage or natural water channels in the area is towards North West and it finally joins the Damsala Nalla flowing NE-SW. It is a perennial stream. In the southern part, the Mahagiri hill range lies at an altitude of 300 m above sea level, whereas Damsala Nalla lies between 100 m to 180 m above sea level. The average rainfall of the area is around 2400 mm/year. The Damsala Nalla crosses the mining belt along the length. This is the main source of water for all settlements and villages; and it brings with it the main drainage water from almost all of the mines. Around twenty perennial streams have originated from the Daitari protected forest area. Another eighteen have originated from the Mahagiri reserved forest and joined the Damsala. The Damsala Nalla joins the Karkhari Nalla before emptying into the River Brahmani that goes to the Bay of Bengal. Thus, the entire Damsala Nalla basin, which has more than 75 villages and 40 perennial streams, is polluted by the discharge of hexavalent chromium.
The Brahmani riverbanks have a large deposit of waste rock even otherwise and the water runoff into the river makes it one of the most polluted rivers. Over 30 million tonnes of waste rock are spread over the surrounding areas and the Brahmani riverbanks.[iv] The contamination of the Brahmani is also affecting the many villages of Bhuban block of Dhenkanal district; Bhuban block is located on the banks of the Brahmani.
Dust caused by mining activities also contains a degree of Cr(VI). Roads are a big carrier of intense dust pollution in mining areas. Seepage water that accumulates in nonoperating quarries gets used by people for bathing and washing purposes. This has the possibility of high Cr(VI) content. Unused mines too can allow such seepage. Abandoned mines face danger of collapse and also allow seepage of toxic hexavalent chromium through the year. Water contamination is happening from water discharge directly from mines, from monsoons when rains flow down from the overburden dumps, and dumps collapsing directly into the water. Many dumps are close to the Damsala Nalla.
Reports from central laboratories of tests conducted by the the State Pollution Control Board of chromite mines in Sukinda valley reveal the presence of hexavalent chromium as much more than the permissible limit from samples collected as recently as October 2018. The Annual Report of ICAR-IIWM[v] shows 70% of water and 28% of soil that were found to be unsuitable for agricultural purpose due to the high toxicity level.
The human cost and the ecological cost of chromite mining is yet to be acknowledged, leave alone any kind of mediation by government or non state actors. How green was my valley!
Ranjana Padhi & Lambodar Mohanto are researchers. This article is based on observations in the area, conversations with local people and studies done on Sukinda. Any feedback or support in terms of ideas and additional information will be highly appreciated.
[i] Wikipedia: Ultramafic rocks are igneous and meta-igneous rocks with a very low silica content and are composed of usually greater than 90% mafic minerals. The Earth’s mantle is composed of ultramafic rocks.
[ii] See the study done in NIT Rourkela, “Environmental Scenario of Chromite Mining at
Sukinda Valley – A Review” by Haripriya Mishra and Himanshu Bhusan Sahu. International Journal of Environmental Engineering and Management, Volume 4, Number 4 (2013), pp. 287-292
© Research India Publications at http://www.ripublication.com/ ijeem.htm
[v] Developing the Process for Remediation of Chromium from Polluted Water Sources; Das and Et Al. IIWM; 2018