De Beers said that the initial plan for the Venetia underground mine in South Africa has been postponed for approximately 12 months.
The delay is related to regulatory procedures and lengthy approvals.
The Mining Weekly publication cited the group's statement that its team in charge of implementing the project "is working effectively and has already been able to halve the time lag by half."
At present, the project is being drilled by the mine shaft, after subversive work began in March to create a slope.
By June 10, a 70-meter tunnel was laid at the mine, Mining Weekly reports.
At the moment, kimberlite rocks are mined on the surface of the Venetian mine with a capacity of 6 million tons per year.
De Beers said that production from tailings to develop additional reserves is 40 to 42 million tons per year.