The 25-year-old from Gravesend, who does not wish to be named, punctured both lungs, broke 17 ribs and suffered major internal trauma during the incident on November 15 2011.
He was in intensive care for eight days and was off work for more than five months.
Westminster Magistrates’ Court heard that his employer, Rollmark Engineering Limited, trading as MRI London, was contracted to move large items of equipment into a lower ground plant room at the hotel.
The injured worker was one of five MRI employees attempting to move a vessel weighing 1.3 tonnes into the room using a chain blocks and hoists.
One worker was operating the hoists, two others were standing alongside the vessel to steady it and the final two, including the injured party, were standing on the edge of a raised ledge to provide further steadying support.
The vessel had been manoeuvred so that two of its feet were on the floor, but as it was being raised to stand fully upright the injured worker fell from the upper level.
At the same time the vessel detached from a load hook and fell on top of him, pinning and crushing him against the edge of the ledge.
An HSE investigation found that although MRI had prepared a risk assessment and method statement for the work it was deficient in several areas.
The statement was lacking detail, the wrong lifting equipment was specified and the assessment was not site specific, failing to acknowledge the actual risks associated with moving equipment down into the plant room.
HSE also found that the lifting equipment being used included a defective chain block hoist that had a missing safety catch.
Rollmark Engineering Limited of Gravesend was fined £12,000 and ordered to pay £14,860 in costs after pleading guilty to safety breaches.
After the hearing HSE Inspector Eileen Gascoigne said: “This serious incident was entirely preventable and clearly demonstrates the need to ensure that lifting operations are planned and managed with the utmost care, especially when they involve heavy items of kit or machinery.
“Had the work been better assessed, and had the right equipment been provided, then the trauma the worker endured could have been avoided.
“He and his colleagues were placed at unnecessary risk, and I hope today’s prosecution sends a clear message to anyone undertaking such operations.”