Mokokchung, 24 September (MTNews): The Department of Geology and Mining, Government of Nagaland has published its report on the fire erupting from a borehole in Tizit that happened earlier this month. The fire erupted from a newly drilled borehole at Pongma Colony in Namsa town, located within the Tizit area of Mon district on 16 September 2023, as reported in this newspaper then. On 18 September, a team from the Directorate of Geology and Mining, Nagaland comprising Toshiakum, a drilling engineer, and Chingao Konyak, an assistant geologist, was dispatched to assess the extent of the gas leakage.
The department’s subsequent report revealed that the incident of gas leakage, specifically biogas, occurred during the drilling process for a borewell water source. Drilling activities had commenced on 12 September, with the gas emission transpiring on 16 September.
The report provided insights into the incident. “The emission of gas occurred when the borehole was dug to about 140ft. The workers in order to check whether the gas was flammable lit the gas. The aquifer was struck at about 80ft to 98ft after which between 98ft to 140ft was clay,” the report said.
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This gas, found to be combustible in nature, burned for nearly three hours. Following the directives of the Superintendent of Police, Mon, and based on advice from the Geology and Mining department, the workers promptly extinguished the fire by filling the borehole with sand on the same day, the report added.
The report further detailed the precise location of the gas leakage incident, pinpointing it within a privately owned plot with coordinates denoting latitude N26°56’42.8″ and longitude E90°03’52.4″. Situated at an altitude of 62 meters, this area falls under the purview of the Singphan Oil Block (ONGC) and Schuppen belt, distinguished by imbricate thrusts featuring the Naga Thrust to the west and the Disang Thrust to the east.
On 18 September, field observations revealed that the gas leakage persisted, accompanied by a hissing sound. Gas detection instruments recorded the following readings: H2S (Hydrogen Sulfide) – OPPM, CO (Carbon Monoxide) – OPPM, O2 – 20.3%, and LEL (Lower Explosive Limit) – greater than 50%.
To mitigate the risks associated with the gas emission, given the LEL exceeding 50% and the substantial release of methane gas, residents were advised to maintain a safe distance from the leakage point. Moreover, residents were cautioned against drilling any borehole within a radius of at least 50 square feet. The borewell was also instructed to be filled with sand to contain the emission.
“DGM with the help of residents will continue to monitor the gas emission for a week or two. Based on further observation, the hole may be permanently sealed,” it stated.
Foothill areas of Nagaland are geologically termed as ‘Belt of Schuppen’ and cover an area of approximately 3000 sq. km, stretching from Mon district in the north to Peren district in the south.
These regions are recognized as zones bearing oil, gas, and coal, with previous reports of hydrocarbon gas leaks in the Schuppen belt. Such gas leaks serve as indicators of the presence of valuable natural resources like oil, gas, and coal, as emphasized in the report.