Minnesota’s farmers will have plenty of questions about trade and tariffs when U.S. Secretary of Agriculture Sonny Perdue makes a scheduled appearance at this week’s Farmfest in Redwood County. Those attending also ought to put Perdue on the spot about another issue critical to the state’s future: protecting the Boundary Waters Canoe Area Wilderness.

The U.S. Forest Service falls under the Ag Department’s organizational umbrella. For almost a year, Perdue has irresponsibly kept secret important information gathered during an aborted Forest Service study of mining’s risks within the wilderness watershed. On Tuesday, Perdue through a spokesman declined an editorial writer’s request to sit down and explain why during his visit to Minnesota.

The study, which was supposed to take two years to complete, was launched by the Forest Service late in the Obama administration. The federal lands adjacent to the BWCA hold valuable deposits of copper and other metals. Twin Metals Minnesota, a company controlled by a Chilean mining conglomerate, has proposed opening an underground mine on land adjacent to the wilderness.

Last September, Perdue announced that the study had been canceled before its completion. Since then, the Trump administration has taken significant steps to advance the Twin Metals project. At the same time, Perdue and other federal officials have refused to release the data gathered during the study. Among those whose requests have been blown off: multiple members of Congress, including Minnesota Rep. Betty McCollum, a Democrat.

The Star Tribune Editorial Board has also unsuccessfully sought the information since April. The Wilderness Society advocacy group is now suing the Trump administration for it. The delays reflect poorly on Perdue’s leadership.

There is no good explanation for keeping secret the data gathered during a taxpayer-funded study. Doing so strengthens Minnesotans’ concerns that politics, particularly lobbying by Twin Metals’ wealthy Chilean owners, is driving federal decisionmaking.

Why can’t the public see the science it paid for? What is Perdue’s agency hiding? Answers are overdue. The secretary’s Minnesota trip offers a chance to provide them.