(Updates casualty toll, adds quotes and details)
RAIPUR, India, Sept 23 (Reuters) - At least 20 workers were killed and about 50 feared trapped when a chimney under construction at a power plant in central India collapsed, police said on Wednesday.
The power plant belongs to Bharat Aluminium Company Ltd (Balco), in which Sterlite Industries (India) Ltd, part of the mining group Vedanta, holds 51 percent.
About 100 workers and engineers were working on the chimney at Balco Nagar, several hours' drive from the Chhattisgarh state capital, Raipur.
"It's a massive accident," Ratanlal Dangi, district superintendent of police, told Reuters by telephone.
"We have retrieved 20 bodies so far. Still many more are trapped under the collapsed chimney's debris. Massive rescue and relief operations are under way."
The chimney, which collapsed after heavy rain and lightning, had reached 100 metres (330 feet) and was designed to be 275 metres high, police said.
Balco spokesman B.K. Srivastava said: "There is an accident and some people are injured."
Raman Singh, the chief minister of Chhattisgarh, ordered a judicial inquiry, according to a statement by the state government. (Reporting by Sujeet Kumar; Editing by Matthias Williams)