Opinion editor's note: Strib Voices publishes a mix of commentary online and in print each day. To contribute, click here.

•••

We live in a big, big world, so whenever something gets to be the biggest, we should pay attention. Right now, the world's largest private equity firm, BlackRock, is trying to buy Minnesota's second-largest public utility. For 150,000 customers, 14 municipalities and several of the state's largest industrial works — including all the iron mines on the Mesabi Range — that could eventually mean big changes.

Last May, a group led by Global Infrastructure Partners and the Canada Pension Plan Investment Board announced an agreement to purchase Allete, the parent company of Minnesota Power. GIP is a subsidiary of BlackRock, providing the heft behind the deal.

How big is BlackRock? It holds about $11.5 trillion in assets, more than the GDP of all nations on Earth except for China and the United States. If BlackRock had a navy, it could sack whole continents. It doesn't, however, because navies don't produce dividends.

Now, big companies buy little companies all the time. How upset should we really be? MP's parent company Allete wants this sale. So do its employee unions. A sale like this will infuse capital into the company's future plans.

For instance, Minnesota Power wants to meet renewable energy and reduced carbon goals. The Clay Boswell plant in the northern town of Cohasset, Minn., is one of the biggest coal-burning plants in the state. As Boswell approaches its end of service, MP announced plans to convert the plant from coal to natural gas. This would reduce carbon emissions and provide baseload generation alongside its renewables.

Plans like this cost big money. Enter BlackRock, with more bucks than an unguarded cornfield.

This sounds pretty good, but we should also be wise to the unintended consequences that a deal like this might carry. When little companies get bought by big companies, things never go back the way they were before. Something new happens.

The Allete purchase is going through an administrative law review prior to a decision by the Minnesota Public Utilities Commission next fall. The public comment period closed last week. Hundreds of comments were recorded alongside testimony and documents provided at a series of hearings. The importance of this deal might best be measured in the fears it seems to have provoked.

Many comments center on worries that an investment firm like BlackRock would prioritize profits over the best interests of Minnesota ratepayers. Still others seem concerned that the infusion of cash would lead to spending on projects that would require future rate increases. Some fear spending on green technology, while others worry that the technology won't be green enough.

In fact, the controversy has Minnesota's largest mining companies lined up on the same side as the Sierra Club to oppose the sale. Meanwhile, several major unions back the deal to preserve their current contracts. The Minnesota Chamber of Commerce also supported the purchase. This deal has enough plot twists and unexpected alliances to merit a reality TV show on CNBC.

Of course, we don't know what the new owners would do if they controlled Minnesota Power. They've said that any potential rate increases would have to go through the PUC anyway, so the public shouldn't worry about that.

But I've learned to watch a particular indicator very closely. How nervous are the mining bosses? They can be as jittery as canaries, and for good reason.

If there's one thing you can count on from mining companies, it's fear of uncertain costs. Throughout history, mining has generated decadent profits and humiliating bankruptcies with equal frequency. Chaff in the budget might be tolerated so long as it is predicted.

But even a faint hint of new expenses — taxes, environmental laws, and yes, electricity rate increases — provokes penny-wisdom bordering on pound paranoia. This is the defining impulse of the steel titan. Like a pig to truffles, this corporate value can't be taught. It is bred over many generations, an instinct akin to breathing.

Minnesota's iron mining industry is stressed right now because of shifting economic conditions and slowing demand for large steel goods. With more than 600 Iron Range miners now on layoff status, companies like Cleveland-Cliffs are pinching pennies. With diesel-electric trucks, electric shovels and drills and massive electrical mills, rate increases could be devastating.

The mines also know better than most how companies like BlackRock operate. Paradoxically, BlackRock holds substantial minority shares in Minnesota's two major mine employers, Cliffs and U.S. Steel. Clearly, those companies know that BlackRock investors will want increased profit over time, something that would necessitate rate increases.

U.S. Steel used to be the biggest corporation in the world, every bit as imposing as BlackRock is today in the financial world. U.S. Steel marshaled its enormous advantages in the early 20th century to corner the market, set prices and control labor costs.

But after a while, the company became too inflexible. It shrank, focused on short term profits, shed tens of thousands of jobs and today waits for someone to invest in its survival. We should not ignore the irony that the U.S. government shot down a Japanese company's proposal to buy U.S. Steel, at least for now, because of the perceived risks.

An administrative law judge will have her say on the purchase of Allete before the state Public Utilities Commission renders the final decision. Let's hope commissioners consider carefully. Under the sway of a privately held juggernaut like BlackRock, this might be the last time the public gets much say at all.