Capita said it is to manage the contract to administer all miners' personal liability claims for the Department of Trade and Industry (DTI).
Capita won the contract over previous supplier Aon, whom it will pay £8m for the underlying infrastructure and other assets.
The contract is for claims relating to certain health conditions caused by working in British Coal mines, said Capita.
It said this was the government's largest uncapped liability, estimated at £7bn, with £2bn having been paid out to date.
The contract will run until 31 July 2006, and Capita said it expected to generate revenues of £125m during this time.
