Robert Mulcaster was the fourth son of John Mulcaster (1685 – 1757) lead smelter for the London Lead Company at Acton Mill. Robert was appointed Blackett’s chief agent at the Blaydon refinery in 1765. He probably started his career as a lead smelter at Acton Mill, but at the time of his appointment to Blaydon he had been employed by the London Lead Company as a refiner at Acton for several years. At Blaydon his responsibilities were wider than managing the refinery. He was also responsible for collecting the rents from the Winlaton estate. In about 1807, after more than forty years at his post, he was replaced by his son John (1782 – 1834) for whom Blaydon House was built. John Mulcaster had previously worked under his father as an under agent. Robert Mulcaster’s older brother James Mulcaster (1721-1805) was joint agent at the Langley Smelt Mills for Greenwich Hospital and the London Lead Company and wrote an account of lead smelting presented as a series of letters to the Lit. and Phil. in Newcastle.
Sources: Yvonne Purdy (pers. comm.), Dukesfield documents
I Forbes and Y Purdy, ‘The Mulcaster Family: a lead mining dynasty’, Hexham Historian Vol 25 (2015)