If you stick to the discipline of buying resource companies at discounts to this value, you'll do well over the long term. Concentrate on companies that have high quality assets, above-average return on capital, and growth potential. When you find these kinds of companies, you can take the commodity price risk out of the equation. In general terms, the outlook for the various industries is dependant on three factors - demand, supply, and, price. Demand is tough to predict and I will not make an attempt.
Supply is much easier to get a handle on.
Other than unplanned supply disruptions, supply growth over the next couple of years is the easiest part of the equation to evaluate. In most resource commodities, production increases over the next couple of years are expected to be relatively non-existent compared to the previous three or four years. The reason is the third factor, which is price. The prices of many resource commodities have been depressed for some time now, and that's hindered the expansion of production capacity. But eventually, that reduced production will contribute to a rebound in prices.