Proposed remedy to mine upward still subject to multi-agency reviews

On April 1, 2024, the Colorado Division of Reclamation, Mining & Safety (DRMS) approved a Technical Revision to the state mining permit held by Rocky Mountain Industrials (RMI) for its Glenwood Springs limestone quarry.

The Technical Revision comes in response to the January 2023 rockslide that occurred at the quarry. DRMS issued a cease-and-desist order, and then negotiated a Stipulated Agreement, signed in April 2023, that allowed some mining activities to continue.

Consultant recommends stabilizing by mining upward

A key document in the approved Technical Revision — a geotechnical report prepared by Kilduff Underground Engineering (KUE) of Denver — recommends stabilizing the slope by mining hundreds of feet higher on the mountainside.

Section 9 of the report states, “It is the opinion of KUE that the upper and lower limestone beds should be removed completely from the highwall to minimize the risk of another release.”

Section 8 of the report states, “The spatial intent of the slope configuration … should be to extend north to where the upper limestone layers pinch out above the current mining activities.”

The location of that “pinch out” area is not clearly described, but the GSCA’s understanding of the geology indicates this would be hundreds of feet higher up the mountainside and well beyond RMI’s current permit boundaries.

In an April 22 email, Amy C. Yeldell, DRMS environmental protection specialist, told the Citizens’ Alliance, “The Technical Revision was for the conceptual plan. It does not authorize activities. A later revision will be required to implement [the plan].”

Agency caveats prevent immediate action

The DRMS approval letter, signed by Yeldell, spells out two caveats that block RMI from acting on the “mining upward” plan.

Yeldell’s letter states, “This Technical Revision does not authorize the operator to initiate the methods discussed in the report. Nor does it allow the operator to circumvent any other agency’s requirements.”

In other words, RMI must also obtain approvals for such a plan from the U.S. Bureau of Land Management and Garfield County, which both hold mining permits for the quarry. RMI faces permit non-compliance problems with both BLM and Garfield County.

In the April 1 letter, Yeldell also told RMI, “A mine plan modification will be required to address specifically how the methodologies for safeguarding will be implemented on site.”

A key interest for state mining regulators is the safety of quarry workers.

DRMS officials have also told the Citizens’ Alliance that the state agency will require a separate process, called a Permit Amendment, if mining or slope stabilization work is proposed beyond the current mining permit boundary (pink line in aerial image at right).

While the Technical Revision was a regulatory action conducted solely between agency staff and the mining company, the Permit Amendment process would include opportunities for public comment, review by other permitting agencies, and a final decision by the Colorado Mined Land Reclamation Board.

Download the DRMS April 1 Technical Revision approval letter here.