The rescue operation continued at Dadam mining site for the second day on Sunday, where four people were killed in a landslide, a day earlier.
"At least one more person continues to be trapped under the debris," Sub-Divisional Magistrate Manish Phogat said, referring to the register that keeps a record of the workers at the site.
He did not rule out the possibility of more persons, such as the helpers, being trapped as their records may not have been maintained.
"The rescue operation is likely to continue until Monday afternoon," Phogat said.
Clearing the big boulders was consuming time, he mentioned.
Apart from the four dead, at least two people have sustained injuries, Phogat said.
After the incident at around 9 am on Saturday, police had said around half-a-dozen dumper trucks and some machines were buried under the debris.
Haryana Home Minister Anil Vij had earlier said several rescue teams, including those from the National Disaster Response Force, State Disaster Response Force and the Army, were pressed into service.
Chief Minister Manohar Lal Khattar had on Saturday issued directions for bringing cranes, fire brigade and other machinery from the adjoining districts to clear the debris so that the people buried under it could be rescued.