After successfully mining in Victoria, in 1869 John Watson Walker was invited to report on Thames mines, and subsequently was asked to stay on as a mine manager. Despite his high reputation as both a manager and company director, in 1881 some shareholders in one company sought his dismissal because he had failed to find rich gold (!). From the 1880s onwards, he envisaged obtaining English capital to enable the development of much larger areas than those traditionally worked. Involved in most Hauraki fields (and beyond) as an investor if not a miner, in the 1880s he was for a time a publican at Te Aroha, and in the following decade acquired a farm nearby. He struggled financially in both decades, and moved from goldfield to goldfield trying to develop his ‘gigantic’ schemes, making several trips to London over more than 20 years in usually fruitless attempts to raise capital. As the first supervisor for the Waihi Company, he investigated new treatment processes, but resigned his position shortly before cyanide was proved to the ideal one. At Thames, his ‘gigantic’ scheme was to work the low levels, and at Te Aroha he attempted to develop a large area of unpayable ground. All his schemes depended not only on attracting overseas capital but on obtaining concessions from both government and union. His last efforts to develop mining on a massive scale were at Waihi, in the early twentieth century. Walker was seen as being a skilled and practical miner, whose opinions were taken seriously. On behalf of investors, he investigated some new areas, and achieved fame for exposing an attempted fraud near Wellington. He attempted to assist the interests of the industry, and urged the need for capital and labour to work together harmoniously. He was outspokenly critical of the Liberal Government’s mining legislation, which he claimed scared capital away. He could be arrogant, as illustrated on several occasions, notably when participating in shooting matches in the early 1870s. And a question must be raised about his treatment of his first wife. But as a mine manager, he excelled, even if his schemes to work large areas were over-sanguine and lacked credibility both because he did not understand the geology and because he over-estimated his ability to raise capital and to get his way with both government and the union.