To enable the output from the mine to be exported, a 3-mile (4.8 km) narrow-gauge tramway was constructed that ran across three viaducts and through two tunnels to the harbour of Port Mulgrave, where ships would take the ore directly to Tyneside.

Part of the site is now underneath the surface workings of the Boulby Mine complex, though some buildings remain at ground level.

[note 1][1] As the company installed their own blast furnaces at the shipyard, iron ore needed to be sourced, and a licence was obtained to mine for ironstone in the vicinity of Easington and Boulby on the Yorkshire coast, which had not been mined for iron before this time, but small scale quarrying of ironstone had taken place before in coastal regions.

[note 2] Iron was dug from the cliffs, and loaded directly into ships in the port underneath the workings, at first on a wooden jetty, which was later replaced by a stone one.

After the conversion of the mine from steam to electricity, a Sirocco Fan and associated buildings were installed on the site which added improved efficiency in venting gases and introducing air from above ground.

[14] Although the new company did still supply Palmer's with iron ore, they sought out new markets as the output from the mine in 1899 was on average 3,000 short tons (2,700 t) per week, which was being stockpiled as they were unable to sell it all.

This allowed the miners to resume full time working and the contract to supply the Pease and Partners steelworks at Skinningrove, meant that the underground transfer was a simpler method of transporting the ore.[16] However, this practice ceased on the outbreak of the First World War.

[17] Additionally, with the possible threat of wartime action at Port Mulgrave, first a rope-worked, then later, an electric incline was installed in 1917, connecting the mine directly with the nearby Whitby to Loftus railway line, which was just to the north.

[18] The site was completely abandoned in June 1934,[19] with an official notice stating that the company had been dissolved appearing in the London Gazette in October 1936.

[33] This had been a previous ironstone working dug into the cliff, which was developed into a brick-lined tunnel for the tramway connecting the dock to Grinkle Mine.

[39] Wooden gantries were built some 60 feet (18 m) above the stone jetties that allowed the mined ore to be laden into the ships by means of gravity.

[42] As the western portal of Port Mulgrave Tunnel was the switchover point for the traction, this is where the tramway had a small shed on a siding off the main running line.

[18] A rope-worked incline was built first, sometime during 1916, when the Boulby and Grinkle Park Mines Company reached an agreement with the North Eastern Railway for sidings to load ironstone.

[50] After 1916, when ore was transferred direct to the railway line, the tramway ceased to be used to output ironstone, but due to the remote location of the mine, it was still used to transport the miners up and down the valley to the minesite.