In the early 1850s Sir Charles Palmer opened his first ironstone mine on his coastal property at Rosedale Wyke. The harbour costing £45,000 was built within a year & was formally opened in 1857. It was built so iron ore could be cheaply transported, by sea, to Jarrow to feed Charlie & George Palmers blast furnaces on Tyneside which produced sreel for the shipyards. In order to avoid confusion with the Rosedale ironworks in the heart of the North York Moors, Palmer renamed his coastal property Port Mulgrave in honour of the Earl of Mulgrave, a prominent local landowner.
When the ironstone reserves at Port Mulgrave began to dwindle Palmer opened another mine a short distance inland at Grinkle. The ore was transported on a narrow gauge railway running over three wooden viaducts and through two tunnels to reach the harbour. In 1916 the Grinkle mine was connected to the nearby Whitby – Middlebrough railway and Port Mulgrave harbour was abandoned.
In 1934 the last of the machinery was sold for scrap and the remains of the wooden gantry accidentally caught fire and burnt down. At the start of the Second World War, the north pier wall was blown up by the Royal Engineers to stop any possible German invasion. Who needs enemies!