Born in 1844 in Nottingham, England as the son of a lace-thread manufacturer, Edmund Harris Thornburgh Plant went on to become one of the most successful businessmen and mill owners in Charters Towers.
After leaving England, and a brief sojourn in America, he arrived in Queensland in 1862 aged 18. His original intentions were to pursue pastoral occupations, and he worked on various stations around Queensland for two years before he took to the Rockhampton goldfields with a partner George Jackson.
When the northern goldfields opened up, he and Jackson followed the rush, first to Ravenswood in 1869 where they set up the first ore-crushing battery in the area, the Vulcan Mill. Once gold was discovered in Charters Towers in 1871, he and Jackson shifted their operations to Millchester, only to find no one had set up mills there yet - all the ore was being sent away for processing, delaying results for the miner's hard work.
He purchased a mill from Cleveland Bay, and had it carted over the rough bush tracks to Millchester, where he built the Venus Mill which was soon a flourishing operation. They sold it in 1872 to James Hutton.
Plant soon moved back to Ravenswood, but by 1883 returned to Charters Towers and created a mill in lower Mosman Street. Initially just a tailings treatment plant, extracting further gold from previously treated ore, after six years he added batteries and commenced crushing as well. He had the Mosman Creek dammed beside his mill, creating a large dam at the end of Mosman Street, which was variously referred to as Plant's Dam, Mosman Dam, or the Bonnie Dundee Dam.
Plant invested in many operations around Charters Towers, including mines, mills, cattle stations and stores and to reflect his growing wealth and status he had Thornburgh House built in 1890 to overlook his mill and dam. Described as one of the largest and most handsome villa residences in the north, it housed Plant and his wife Elizabeth (nee Hodel), daughters Maria, Armenia, Rosa, Emelie, Maggie, Katie and sons Edmond and George. It held a school room for his children, as well as a basement playroom and roller-skating rink. The beautiful grounds were landscaped and created a green oasis in the town.
Thornburgh house became a social hub for the upper echelon of Charters Towers society, as Plant and his wife Elizabeth were members of many local boards and committees, including the Dalrymple Divisional Board, Chamber of Commerce, Water Board, Hospital Board and even the Townsville Harbour Board.
Plant lived at Thornburgh House for 30 years and was a popular and prominent citizen. When the fortunes of the Charters Towers goldfield began to decline, he made one last bid to raise its status and invested in the Day Dawn Deep mine on Marion Street. It was not a successful venture, as the levels were troubled by flooding.
Plant eventually decided to live out his final years in the south. He sold Thornburgh House to a committee formed by the local Methodist and Presbyterian Churches for just £3000 as a charitable gesture so they could establish a college there. It became Thornburgh Boys College, which later added Blackheath Girls College, and eventually amalgamated to become Blackheath and Thornburgh College.
Meanwhile, Plant first retired to Goose Lagoon, his sugar farm near Ingham, then finally moved to Sandgate in Brisbane, where he died in 1926 aged 82. He was remembered in Charters Towers as a capable and progressive thinker and is said to have been the first person to have installed electricity both domestically and industrially. Plant's driving force as a miner and his investment in the town helped to prolong the success and prosperity of the Charters Towers goldfield, with an added legacy in the thriving education field.