Andrew Darling was demonstrating a crusher machine, which is used to squash stone and concrete, to workers at Dalkeith firm Neil Williams Haulage Ltd when he was himself crushed to death by the machine.
The Bonnyrigg dad is believed to have received fatal injuries in front of around six traumatised witnesses at Mayfield Industrial Estate at 1.55pm on Wednesday.
Police officers and the Scottish Ambulance Service rushed to the scene where paramedics pronounced Mr Darling dead despite attempts to save his life.
It is believed during the SCG Supplies Ltd employee’s demonstration, he entered the maintenance hatch of the crusher, which was not secured.
A gust of wind is said to have blown the hatch door shut and as a result, a metal plate fell on the former Newbattle High School pupil’s chest.
Police confirmed to the Evening News that Mr Darling had been “crushed” by the industrial machinery.
Health and Safety Executive inspectors have attended the scene and are working in conjunction with Police Scotland.
The Dalkeith depot was immediately closed down following the incident and remained closed last night.
A spokesperson for Neil Williams Haulage Ltd said: “Andrew was working for SCG Supplies Limited and was demonstrating a piece of equipment to the NWH Group.
“We extend our deepest sympathies to the friends and family of Andrew at this sad time.
“The depot will remain closed at the moment. We are looking to have re-opened by the end of the week.”
SCG Supplies is an independent supplier of spare and wear parts for the crushing, screening and recycling industries in the UK.
Andrew had been a worker at SCG Supplies Ltd since September last year after more than a decade working at Neil Williams Haulage Ltd.
SCG Supplies Ltd did not respond when asked to comment by the Evening News.
Mr Darling’s wife and daughter were being comforted by friends and relatives last night.
Friend Charlie Henderson led online tributes to the popular engineer. He said: “So very sad, he was a great guy and will be sadly missed. RIP mate. Still can’t get my head round it, he was a really nice guy.”
Willie Gilbertson said: “Can’t stop thinking about this. You were a guid yin big felly! We’re all in shock.”
Gordon Renwick said: “Tragic. Thoughts to the man’s family at this awful time.”
A HSE spokesperson said: “HSE is aware of the incident and inspectors have attended the site. Police Scotland currently have the lead on this joint investigation with HSE.”
A Police Scotland spokesman said: “Police in Midlothian responded to the Mayfield Industrial Estate in Dalkeith at around 1.55pm on Wednesday 20th June following reports a man had suffered serious injuries on the premises.
“The Scottish Ambulance Service were also in attendance and the 47-year-old was pronounced dead at the scene.
“Officers are liaising with the Health and Safety Executive in relation to this incident and a report has been submitted to the Procurator Fiscal.”