A congressional commission in Chile has blamed the mine owners for the rockfall which left 33 men trapped underground for 69 days last year.
The commission said Alejandro Bohn and Marcelo Kemeny were guilty of negligence, a charge they deny.
The investigation also concluded that the Chilean mine safety regulator bore some responsibility for failing to enforce its rules.
Workers said the mine lacked basic safety standards.
The commission unanimously found mine owners Alejandro Bohn and Marcelo Kemeny responsible for the collapse in August 2010, which cut off the miners at a depth of more than 700m (2,300ft).
Alejandro Garcia Huidobro, who lead the congressional commission, said Sernageomin, the state body tasked with regulating the industry, was "administratively responsible" for the accident.
The commission has handed Mining Minister Laurence Golborne suggestions on how Sernageomin could be improved.
Congress is expected to vote on the suggestions put forward by the commission on Thursday.
Mr Golborne praised the work of the commission, which took five months to draw up the report.
He said some work had already gone into strengthening Sernageomin by increasing its budget and the number of safety inspectors.
Relatives of the miners and some of the men themselves have fiercely criticised the mine owners, accusing them of ignoring safety guidelines, and Sernageomin for not closing down the company despite three deaths at its mines over six years, and dozens of accidents.
The BBC's Gideon Long in Santiago de Chile says some of them are pursuing legal challenges against the mine owners.
He says the miners want compensation, and some of them have said they would like to see Mr Bohn and Mr Kemeny sent to jail.
The fate of the 33 men trapped in a hot, dark tunnel for 69 days gripped the attention of people around the world.
Millions watched as they emerged one by one from underground after a massive rescue operation had managed to drill a hole large enough to pull them to the surface.