A member of the public found the body of 24-year-old Miss Mayo in woodland in Ault Hucknall, near Glapwell, just over a mile from junction 29 of the M1.
The student teacher had been raped, beaten about the head and strangled with a length of flex before being dumped in the woods.
It is thought Miss Mayo was murdered while hitch-hiking to Catterick, north Yorkshire, to fetch her boyfriend's car.
Her murder sparked the biggest manhunt the country had seen at that time.
The investigation was eventually scaled down but never stopped.
This week, a Derbyshire Constabulary spokesman said: "47 years on and Derbyshire CID still hasn't given up on the investigation into the murder of Barbara Mayo. .
"The investigation remains open to this day.
"If you know anything, call us on 101."