Dunn's intestinal fortitude is responsible for his claim to at least two significant innovations in the industry. Hematite ore was the foundation of the steel industry in 1935, and it was indeed exploited by Algoma. Next to a hematite deposit owned by Algoma was a mountain more than 1,000 feet high but it contained a low-grade ore called siderite. The experts unanimously declared that Dunn, who wanted to exploit this mountain of siderite, was mad. Nowhere else in the world was an ore of this grade in commercial use. In the early months of 1939, a pilot process seemed to indicate success, but in order to be ascertained it would require full production. Dunn carried the investment through to the end and a positive result was his reward. The next innovation which Dunn developed into production at Algoma was then known as the "Sink-Float process". The need for innovation was due to the exhaustion of ore supplies at the Helen mine. The process, which had been established at Broken Hill Proprietary by Guillaume Daniel Delprat at the turn of the century because of a similar exhaustion, had been tried once or twice in the US but on ore quite different from that at the Victoria. No Canadian mines had developed this technique; no large-scale equipment was available for experimentation and so the pilot plant would be uncertain and expensive. The gamble was a success, and Dunn pioneered again. The Victoria mine was able for a time from 1945 to supplant the Helen mine, while the latter changed from an open-pit to, in 1949, an underground operation.