I think in a business where the rarety of big profitable deposits in safe zones will become a big issue in the near future

Sumitomo CEO would agree with you....Along side Keevil who owns 51% of Temagami, they own 49% of Temagami (Teck A shares)...

Sumitomo Metal Mining Co., Japan’s top nickel producer, will slow the pace of investments in the next three years and shift focus to spending on raw material assets as competition for resources intensifies.

“Resources in good condition are becoming rarer and resource nationalism is continuing to evolve” even as the global business climate improves and currency volatility slows, according to the statement.

Sumitomo Metal, the second-biggest copper smelter in Japan, will seek partnerships with Freeport-McMoRan Copper & Gold Inc.,Vale SA, and Teck Resources Ltd. for access to new copper projects, Kemori said.

Sumitomo Metal, which also refines metals and makes material for batteries and wires, plans to spend about 45 billion yen on buying stakes in copper and other metal deposits to expand its resource base, Chief Executive Officer Nobumasa Kemori told reporters in Tokyo today.