Balco Nagar (Chhattisgarh), Sep 24 - The rescuers early Thursday continued their search for survivors under the debris of an under-construction power plant chimney here of the Bharat Aluminium Company Ltd (Balco) that caved in Wednesday amid heavy rain killing at least 20 labourers.

Dozens of people were waiting at the crash site to know the fate of their loved ones who are belived to be trapped under the rubbles. The workers were employed by the Gannon Dunkerley and Company Ltd (GDCL).

The under-construction chimney would have reached a height of 275-metres on completion but collapsed midway at a height of 100 metres Wednesday afternoon. The chimney is being built for a 1,200 MW coal-fired power plant of Balco.

Meanwhile, the workers have protested against the Balco management and GDCL for alleged security lapses.

The tension, however, eased out after district authorities boosted police presence and assured the workers of stern action against Balco for 'deadly lapses'.

Korba district collector Ashok Agrawal said the toll could increase. 'I estimate not less than 50 people, most of them workers, were still under the rubble.