During his second tenure at Denison, Cliff was faced with the biggest challenge of his career thus far.

The development of nuclear power at an accelerating rate since 1965 had focused world attention on the sources of uranium to fuel the nuclear reactors of the 1970's and 1980's. It was evident that world demand for uranium in the early seventies would exceed the present capabilities of the mining industry.

The projected nuclear generating capacity and the requirements of uranium oxide, annual and cumulative, that were reported a year earlier, now had to be sharply increased as a result of the rapid growth in announced plans for power plants and world recognition of the economies and advantages of nuclear fuel for power generation.

In 1966, Denison Mines was negotiating with six major nuclear power companies in Japan for the purchase of all of the Company's uranium production. This was the first far reaching contract for the Canadian mining industry outside of North America.

The highlight of -67 was the contracts entered into with Japanese companies for the supply of U₃O₈ over a long term. Japan, as one of the world's great industrial nations with limited national resources for electric power generation, would be a major user of uranium and it was estimated that the aggregate demands would be in the order of 100,000 tons of U₃O₈ by 1985.

The contract required that Denison increase its production, while decreasing its costs through productivity and technology changes and, at the same time, maintaining its safety standards. In order to fulfill the Company's obligations of the contract, Cliff initiated extensive research work in the development and use of new mining methods and updated existing underground equipment which would eventually result in the desired increase to productivity. In addition, the changes included expansion of the Company's ventilation system and safety practices.


In 1969, Clifford was offered a senior technical role for the newly created Australian and Indonesian division of Inco as Vice President, Operations.