59-year-old Garg had suffered a cardiac arrest and was hospitalised here on June 12.
Garg, who was also one of the directors of Singareni Collieries Company Ltd, a state government-owned entity, had arrived here on June 12 to attend a meeting, a company spokesperson said.
On the same evening he collapsed and was immediately admitted to a hospital. He was in coma since then and passed way today, the spokesperson said.
Garg had taken over as Chairman-cum-Managing Director of Western Coalfields Limited in 2007.