In the Spotlight

News & Features
A Shortage of Stone?
by Mary Losure
January 26, 2000
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When people worry about urban sprawl, they often think of development paving over corn fields and green spaces . But subdivisions and shopping malls are spreading over more than open country; they're also threatening to cover up metro-area gravel deposits needed to build future roads, houses and shopping malls.

EVERY YEAR, the Twin Cities metro area uses well over a million tractor-trailer loads of what's known in the building trade as "aggregate," the sand, gravel, and crushed rock used to make concrete and asphalt.

As housing developments, highways, and shopping malls spread across the countryside, the demand for aggregate has risen dramatically. Now, in an ironic twist, urban sprawl is threatening to pave over the raw material needed for more urban sprawl.

Jonathan Wilmshurst , director of Minnesota operations for the British-based company Aggregate Industries PLC, drives by a farm field just south of the Twin Cities suburb of Rosemount. Underneath the field is a deposit of prime aggregate, one of a limited number left in the metro area. Wilmshurst says his company won't even try to open a mine there. The housing developments spreading out from Rosemount are simply too close.
Wilmshurst: We don't need conflict and if we can find ways to avoid it we do. If you know that the whole area's going to be covered in houses within two or three years, then there's no way that you're going to be able to identify resources, be able to afford them, be able to get them permitted and operational, before you're surrounded by homes.
Aggregate Industries recently decided to close down its gravel mine in Shakopee after the company failed to get a city permit to expand its operations. Wilmshurst says it made more economic sense to sell the land for industrial development than it did to try to mine it.
Wilmshurst: There isn't enough of a difference to be worth getting into a dispute with the city over. Nevertheless, the Twin Cities just lost 15 to 20 million tons of resource, which was relatively close in , had good road access, wasn't disturbing anybody and that will have to come from somewhere else now.
The Metropolitan Council, which is charged with guiding urban development issues in the Twin Cities, estimated in 1985 there was a 200-year supply of aggregate in the metro area. By the Met Council's current estimate: if no new mines are opened, the supply will be gone in 15 years.

Industry representatives say if they have to mine further and further from the Twin Cities, the cost of aggregate will rise dramatically. Rock is so heavy that trucking it 30 miles doubles its price.

Gene Wright of the Aggregate and Ready Mix Association of Minnesota says that increase means cities could pay millions of additional dollars for roads and public buildings.
Wright: A city of 100,000 - which is roughly the size of Duluth - for every 10-mile haul, it would cost the city of Duluth $1 million a year extra to pay for that aggregate and if that 10 miles trip became a 30- or 40-mile trip, that $1 million suddenly becomes 3 or 4.
Wright says hauling aggregate longer distances will also mean thousands of extra trucks on metro-area highways, further adding to traffic and congestion. But while the problem is clear, the solution is not.

In an attempt to smooth the process of opening new mines, the industry plans to ask the Legislature to transfer some permitting decisions from local governments to state agencies.

The proposal is not likely to go over well with counties and cities. David Wierens is policy analyst with the Association of Minnesota Counties.
Wierens: The big issue is counties losing a piece of control, we think the permitting of gravel mines fits very directly into the zoning and other environmental management responsibilities of counties, and I think to take that away would be a disservice to the people of Minnesota.
Wierens says counties do recognize the need for nearby sources of gravel, especially for roadbuilding. But he says he thinks its going to be harder and harder to open mines as the metro area population increases.
Wierens: It's very difficult for counties to disregard local concerns who really do worry about the fact that these large trucks are driving by, the vibrations, the dust, the noise and the impacts to their property values, concerns about the health and safety of children playing in the streets. It's a balancing act of all these needs as well as the need for gravel.
The aggregate industry has floated the idea of protecting prime gravel deposits though zoning laws, but Remi Stone of the League of Minnesota Cities is doubtful that approach will get too far. She says cities are under intense pressure to develop
Stone: Within our state, we have such a great explosion of population, those property owners that purchased land with the anticipation that they're going to developing it, have an expectation that they will be able to develop it under existing zoning and we have hundreds of thousands of people that will be coming into the state within the next 20 years, and we need to house the people somewhere.
The aggregate industry has been trying to raise awareness of the aggregate shortage and the problems it could cause, but it's an uphill battle. According to industry figures, it takes 120 tons of aggregate to build a new home, and every Minnesotan uses 58 pounds of aggregate a day; but most people don't give much thought to where it comes from now, or in the future.