Arthur Jamieson, 58, from Keith, Banffshire, was working beneath the digger on 21 November 2008 at Parkmore Quarry, Dufftown, Aberlour, when the vehicle rolled backwards, crushing him.
His employer, Leiths Scotland Limited, was prosecuted by The Health and Safety Executive over the incident.
Elgin Sheriff Court heard mobile plant fitter, Jamieson, was fixing a transmission leak on the five-and-a-half tonne digger.
The vehicle was raised on a ramp, but its rear wheels were inadequately secured. Jamieson was crushed when the vehicle rolled off the ramp, and was suffocated as a result of a wheel compressing his chest.
HSE’s investigation concluded that Leiths Scotland Limited failed to provide adequate information, instruction, training and supervision to Jamieson to prevent any risk to his health while working for them.
Jamieson had not previously carried out the task and was expected to establish his own method of raising and supporting the vehicle above the ground.
He was left to organise suitable blocks to support the digger without direct supervision or suitable instructions.
The company, based in Rigifa, Cove, Aberdeen, pleaded guilty to breaching health and safety laws.
After sentencing, HSE Inspector Norman Buchanan said: “This tragic incident should have been avoided.
“Although Arthur Jamieson was undoubtedly an experienced mobile plant fitter, he had not previously carried out this particular task for this firm.
“He should have received adequate information, training and supervision from his employers, which Leiths did not provide.
“It is wholly unacceptable his employers left him unsupervised to devise his own means of working on such a risky repair job.
“Had Mr Jamieson been adequately supervised, he would not have been able to start working underneath the digger when it was inadequately secured at the rear and therefore able to move from its position on the ramps. As a result his death could have been prevented.”