There ensued a long bitter struggle, most of it falling on the junior partner with the Quaker conscience, to make good the losses without actually putting the firm out of business. For going on with the business was essential to the making good. It was a gruelling four years' struggle, but with success at the end of it. And then the American engineer, now grown forever out of youth to the man who had experienced the down as well as the up in life, gave up his connection with the firm and launched on that career of independent and self-responsible activity which has been his ever since. This was in 1908. Hoover was now thirty-four years old and probably the leading consulting mining engineer in the world. His work soon took him back to Australia, the land of his first notable success, but this time into South Australia instead of West Australia. Here he took personal charge of a large constructive undertaking in connection with the rehabilitation of the famous Broken Hill Mines. These mines were in the inhospitable wastes of the Great Stony Desert, four or five hundred miles north of Adelaide, the port city. The living and working conditions in the desert were a little worse than awful, but by his technical and organizing ability he brought to life the two or three abandoned mines which constituted the Broken Hills properties, and, adding to them some adjoining lower grade mines, converted the whole group from a state of great but unrealized possibilities into one of highly profitable actualities. An important factor in this achievement was his origination and successful development of a process for extracting the zinc from ores that had already been treated for the other metals and then cast aside as worthless residues. There were fourteen million tons of these residues on the Broken Hills dumps and from them he derived large returns for the company that he had organized to purchase the property. He also introduced new metallurgical processes for the profitable handling of the low-grade sulphide ores that constituted most of the mineral body of the mines. Indeed, this work in South Australia did much to help prove to him what has long been one of his cardinal beliefs, namely, that the safe backbone of mining lies in the handling of large bodies of low-grade ores. When such great ore-bodies are given the benefit of proper metallurgical processes and large organizing and intelligent building up of exterior plants, mining leaves the realms of speculation and becomes a certain and stable business operation.