Six persons were killed and at least four were injured after a stretch of a stone mine caved in near Bahadurpur village in Birbhum's Nalhati on Friday afternoon.
A police source said altogether 10 people were brought to Rampurhat Medical College and Hospital, where doctors declared six of them dead on arrival.
"Six people were killed in the stone mine accident. We have registered a specific case and will find out whether there were any lapses on the part of the mine owner," said Amandeep, Birbhum police superintendent.
Of the four injured, one was shifted to Burdwan Medical College and Hospital as his condition deteriorated.
A source said that among the multiple private stone mines in Nalhati, excavation was being carried out in the Bahadurpur stone belt area. Birbhum has over 200 stone mines and crushing units and is known as a principal source of stone chips for Calcutta and other states for the construction industry.
Although the exact reason behind the subsidence of a portion of the earth and stone layers is yet to be confirmed, local sources suggested two possible causes.
First, the accident may have occurred during a routine explosion carried out to excavate boulders. Second, some mine workers may have been drilling holes in the stone layers to prepare for blasting.
"We are probing all possible reasons. It must be verified why all safety measures were not followed when workers were deployed in the mine," an official said.
According to sources, four of the six deceased persons have been identified. The four were identified as Lalbabu Sheikh, 22, Samiul Mollah, 25, Ratha Mandal, 30, and Hazrat Ali, 24.
"All the deceased and injured persons were residents of local villages and had been working in the mine for years," said a source.
Nalhati's Trinamool Congress MLA Rajendra Prasad Singh immediately rushed to Rampurhat Medical College and Hospital to meet the family members of the victims.
"I have heard that six people were killed and a few were injured. However, I am yet to know the reason behind the accident. The administration will investigate if there were any lapses in worker safety," said Singh.
A police source said the owner of the mine went into hiding after the incident.