Investigative unit AmaBhungane says it's in possession of board meeting minutes showing that Gupta-linked Tegeta threatened to cut coal supply at an Eskom power station this Friday.
Tegeta Exploration and Resources has been supplying coal to Eskom and threatened to cut the coal supply to Hendrina power station.
The Gupta-linked firm wanted the power utility to increase the rate of payment.
AmaBhungane's Susan Comrie says Eskom only had a seven-day coal stockpile for the Hendrina Power Station earlier this week.
Meanwhile, Eskom has urged households not to panic and says load shedding is not a risk at this stage.
However, the Gupta's legal representatives have told Comrie that they will shut down the supply if Eskom is unwilling to negotiate.
We were able to get our hands on some leaked minutes of a board meeting that happened on Friday last week.— Susan Comrie, AmaBhungane Journalism
The minutes are very clear. They were threatening to pull the plug at midnight on Friday unless Eskom renegotiated the price.— Susan Comrie, AmaBhungane Journalism
Eskom don't have enough coal on their stockpiles.— Susan Comrie, AmaBhungane Journalism
Hendrina Power Station is almost exclusively supplied by one mine; the Gupta's Optimum mine.— Susan Comrie, AmaBhungane Journalism
The coal supply is very low. Eskom don't have enough coal on their stockpile to make up for that situation.— Susan Comrie, AmaBhungane Journalism