The Star Tribune’s Sept. 2 editorial (“Competing visions of mining’s impact”) is exactly right — Minnesotans need a serious, fact-based conversation about the future of specific mining proposals in the state. Our ability to move debate beyond caricatures about who is “anti-” or “pro-mining” depends on accurate information and clear-eyed analysis. Rather than slogans, Minnesotans deserve candidates who understand economic reality and are informed by rigorous scientific studies.

But the so-called “study” of the Center of the American Experiment (CAE) does not contribute much to such a conversation. The CAE report cited in the editorial argues that Minnesota has vast titanium, manganese and copper-nickel resources. Geologists have known about these deposits since the 1940s, yet they remain undeveloped. The obvious question is why. The CAE report doesn’t really answer this question, though it implies permitting delays are to blame.

The truth is simpler: These projects are economically risky.

The Longnose titanium deposit, described by CAE as the “largest and richest ilmenite deposit in North America,” was acquired by Cardero Resources, then abandoned. Why? Because contaminants in the ore make it difficult to process. While University of Minnesota Duluth research is attempting to solve this problem, no funders have stepped forward to finance development of this mine.

The Star Tribune’s recent report on the Emily manganese deposit, “Crow Wing Power’s $20-million-plus investment in manganese mine raises questions” (startribune.com, Aug. 31), is also instructive. Described by the CAE as the “richest known deposit of manganese in the United States,” the mine has found no partners and no money to fund its development. Why? Because prices for manganese don’t justify the investment.

Minnesota’s copper-nickel resources are also economically risky. CAE describes these deposits as “some of the largest undeveloped deposits” of their type in the world. These deposits were identified in the 1940s. For 60 years, an ever-changing roster of mining companies has declined to invest the money to develop these resources. Why? Because they are low grade (averaging just 0.3 percent copper), making them a financially risky investment.

PolyMet, the most advanced of these proposals, decided a projected 14 percent return was too low to proceed in the early 2000s. Its recently updated economic study estimates an even lower return of 9.6 percent. Over the last decade, almost a third of all mining investments in the world were completely written off as a loss, and when the risk of losing all your money is so high, returns like 9.6 percent just don’t cut it.

Glossing over these facts to tout thousands of jobs that could be created if we just “unlock” our mineral resources does not advance the serious conversation Minnesotans deserve and need. If these deposits were as profitable and easy to mine as described, they would have been mined a long time ago. The danger of wallpapering over these shortcomings is the temptation to lower standards or provide public subsidies for economically risky proposals. The Star Tribune and CAE rightly point out the need for high standards to protect workers and our water. But economically risky mines are the most likely to cut corners. Lower-grade deposits, operating on the edge of profitability, create more waste and use riskier practices of mine waste disposal.

Minnesotans should know that our standards for these types of mines have never been tested and haven’t been substantially updated since the 1990s. Meanwhile, Montana, New Mexico and Michigan have adopted higher standards for mine waste disposal, dam safety and water treatment than ours. Mine waste dam collapses in Canada and Brazil that fouled water and killed workers and people downstream demonstrate what is at stake.

Minnesotans should be proud that all sides in the debate about new mining proposals agree on the need for high standards that protect workers and the environment. We hope the Center of the American Experiment joins us in pushing for standards that reflect industry best practices. Other states they hold up as examples in their report have adopted many of them.

During this election season, Minnesotans should demand better. Candidates who only understand slogans won’t make good policy choices if elected. A realistic view of our mineral resources and a commitment to high standards is the best place to start the conversation.

Kevin P. Lee is senior staff attorney and mining program director at the Minnesota Center for Environmental Advocacy