Warren Buffett attracts a lot of attention. As the world's third-richest person and most celebrated investor, thousands try to glean what they can from his thinking processes and track his investments.

While we can't know for sure whether Buffett is about to buy Cliffs Natural Resources (NYSE: CLF) -- he hasn't specifically mentioned anything about it to me -- we can discover whether it's the sort of stock that might interest him. Answering that question could also inform whether it's a stock that should interest us.

In his most recent 10-K, Buffett lays out the qualities he looks for in an investment. In addition to adequate size, proven management, and a reasonable valuation, he demands:

  1. Consistent earnings power.
  2. Good returns on equity with limited or no debt.
  3. Management in place.
  4. Simple, non-techno mumbo jumbo businesses.

Does Cliffs Natural Resources meet Buffett's standards?

1. Earnings power
Buffett is famous for betting on a sure thing. For that reason, he likes to see companies with demonstrated earnings stability.

Let's examine Cliffs Natural Resources' earnings and free cash flow history:

Capital IQ, a division of Standard & Poor's. Free cash flow is adjusted based on author's calculations.

Over the past five years, Cliffs' earnings have fluctuated to a fair degree, though they've remained positive.

2. Return on equity and debt
Return on equity is a great metric for measuring both management's effectiveness and the strength of a company's competitive advantage or disadvantage -- a classic Buffett consideration. When considering return on equity, it's important to make sure a company doesn't have an enormous debt burden, because that will skew your calculations and make the company look much more efficient than it actually is.

Since competitive strength is a comparison between peers, and various industries have different levels of profitability and require different levels of debt, it helps to use an industry context.

Company

Debt-to-Equity Ratio

Return on Equity

5-Year Average Return on Equity

Cliffs Natural Resources 61% 38% 26%
Alpha Natural Resources (NYSE: ANR) 29% 5% 19%
Arch Coal (NYSE: ACI) 70% 10% 13%
Teck Resources (NYSE: TCK) 29% 10% 21%

Source: Capital IQ, a division of Standard & Poor's.

Cliffs Natural Resources produces a fairly high return on equity while employing moderate debt.

3. Management
CEO Joseph Carrabba has been at the job since 2006.

4. Business
Mining isn't particularly susceptible to technological disruption.

The Foolish conclusion
Regardless of whether Buffett would ever buy Cliffs Natural Resources, we've learned that, while earnings have been volatile to some extent, the company exhibits some of the characteristics of a quintessential Buffett investment: high returns on equity, tenured management, and a straightforward business.

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