sentences:  Each ship on average required 15 tonnes of copper applied on average as 300 plates.All the copper was supplied by British mines (the only country in the world at that time that could do so), the largest mine being Parys Mountain in Anglesey, north Wales.The Parys mine had recently begun large-scale production and had glutted the British market with cheap copper; however, the 14 tons of metal required to copper a 74-gun third-rate ship of the line still cost £1,500, compared to £262 for wood.