The Trump administration should swiftly release the data, documents and analysis it relied on to make a controversial 2018 decision advancing copper mining near Minnesota's Boundary Waters Canoe Area Wilderness.

Until it does, disturbing questions remain about whether that industry-friendly outcome was driven by science or politics. If there's nothing to hide, there should be no delays in providing this information to the public.

Minnesotans in particular deserve assurances that federal officials acted in good faith last September when they abruptly ended a two-year study on the dangers posed to the BWCA by acid runoff. That smooths the path for federal officials to renew mineral leases, a key step forward in the long regulatory process that the Twin Metals project must clear.

The project, which remains years away from final approval, would not be located within the BWCA. But it would be right on its edge, with an ore-processing facility proposed 0.38 of a mile from the shoreline of a lake whose waters flow into the protected wilderness. Federal officials last fall justified the study's cancellation by saying no new information about risks to the BWCA or the region's recreation­-based economy had come to light before the scientific study was halted about 20 months into a 24-month review.

Instead of making the information gathered for the study public, two key agencies with oversight — the U.S. departments of Agriculture and the Interior — have kept it under wraps for months despite repeated high-profile congressional requests and an editorial writer's inquiry. It is not clear when, or if, top officials will reverse course.

The stonewalling continued last week during an exchange between U.S. Rep. Betty McCollum, D-Minn., and Secretary of Agriculture Sonny Perdue. McCollum chairs an influential appropriations subcommittee. Perdue appeared at a hearing. McCollum, who began requesting the BWCA study information last September and has repeatedly followed up, made her displeasure with the delays clear.

Perdue did not have a satisfactory explanation for why it's taken months to fulfill this request, and he failed to provide a date for the data's release. His performance only heightened concerns about BWCA pollution.

"Secretary Perdue is fabricating reasons to justify a decision that has only one coherent explanation: The study was canceled because they were afraid it would show that copper mining in the watershed of the Boundary Waters would be devastating and irreversible to the wilderness," said Tom Landwehr, former Minnesota Department of Natural Resources commissioner who is now the executive director of the Campaign to Save the Boundary Waters. "And that wasn't convenient with their plans to try and ram the Twin Metals project through."

Twin Metals officials declined to comment this week on the federal foot-dragging. A spokesman also declined to say whether the mining project had been given the scientific data McCollum wants.

The mining industry has an abysmal environmental record, often leaving U.S. taxpayers on the hook for billion-dollar cleanups of polluted wastelands. Companies now looking to tap northeast Minnesota's rich metal deposits have tried hard to distance themselves from this, providing assurances that technology and stronger regulations would prevent a new round of abuses.

The brazen disregard for transparency on the Twin Metals project makes a mockery of the "things-have-changed" claim. If mining can be done responsibly, then the facts and science will support this. The data ought to stand up to public scrutiny — a cornerstone of modern oversight.

Concerns about political influence on the federal Twin Metals decision must be taken seriously. A last-minute move to protect the BWCA by President Barack Obama may have ramped up lobbying by Antofagasta, the project's wealthy Chilean owners. It also may have spotlighted the project for an incoming administration with an anti-regulatory agenda.

Did that play a role? That's a question, along with others, that can't be answered without seeing the new study data. The public paid for this information. It has every right to see it.