A china clay company says it regrets the "unfortunate impression" left after the cheap sale of land in Cornwall.
Joan Vincent said she was happy with the result of the investigation
Two plots of land were sold between 2001 and 2003 to local councillor Joan Vincent for £7,500. They were then sold by her for a total of £170,000 in 2005.
An investigation has concluded that the company's estates department made errors by selling some land too cheaply and not including covenants in a sale.
Mrs Vincent said she felt vindicated at the findings.
Imerys began its investigation last October into the sales by Imerys Minerals Limited of two adjacent parcels of land from its estate at Treverbyn to Restormel borough councillor Mrs Vincent.
They were part of several parcels of land being sold off because they were surplus to Imerys' operational requirements.
The investigation, conducted by an independent firm of solicitors, concluded that the 2001 sale for £2,500 was reasonable for the value of the land.
But it found that the land sold to Mrs Vincent in 2003 for £5,000, was lower than the market value.
Restrictive covenants prohibiting development on the land and ensuring Imerys was paid extra for the increase in the land's value were not included, the report said.
The investigation decided that the company's estates department had made an error in failing to include the covenants.
It said that controls were in place to stop such incidents from happening again.
The company said: "Imerys Group is fully committed to transparency, probity and honesty in all its dealings.
"Imerys Group therefore regrets any unfortunate impression which might be drawn from the 2003 property sale to Mrs Vincent."
Mrs Vincent said she was relieved at the investigation's findings and she had been adamant all along that she had done nothing wrong.
She said: "I'm very happy with the result of the investigation, I feel vindicated."