An upgrade to the railway line is needed say the council
Upgrading a railway link could inject an estimated £43m into a Gwynedd town's economy, according to a council.
Gwynedd council says there is a market for slate waste in Europe and wants to exploit it the product from the Blaenau Ffestiniog area.
It would mean Welsh Assembly Government investing at least £19m on the Conwy Valley line, but the authority argues that it would be worthwhile.
The assembly government said it would examine the potential for upgrading.
"The assembly has given similar grants in connection with public transport and railways in south Wales, and I think that to cut the cake equally, this investment would be an excellent investment for years to come," said Gwynedd councillor Gwilym Euros Roberts.
"If you put it in perspective I think it is a good investment of public money," he added.
Mr Roberts, along with council leader, Dyfed Edwards, and the head of Gwynedd's economic development, Sioned Williams, travelled to Cardiff on Tuesday to speak to Economy Minister Ieuan Wyn Jones about the upgrade.
The assembly government said Mr Jones had undertaken "to consider the council's proposals further and investigate the potential interest in upgrading the Conwy Valley line".
The council believes there are millions of tonnes of slate waste in Blaenau Ffestiniog which could be used for Europe-wide road building and construction.
To take advantage of it however would mean the rail line between the town and Llandudno Junction would have to be improved.
Fifty new jobs could be created in the town as part of the redevelopment but associated economic and environmental improvements to the area could be around £43 million.
Mr Roberts said that taking advantage of the slate waste would also help the assembly government meet its own target that a quarter of all aggregate produced in Wales should be secondary or waste.
Andrew Roberts from the town's Greaves Welsh Slate Company welcomed any development.
"This would be excellent for the area," he said.
"It would secure jobs and allow the slate industry to take advantage of markets across the world, not just in Great Britain," he added.