In a careful search of state public records, the Citizens’ Alliance has learned that the U.S. Mine Safety and Health Administration (MSHA) approved a revised mining plan for the RMI limestone quarry on July 7, 2023.
MSHA stepped in to enforce quarry operations with a stop-work order on Jan. 19, 2023, one day after a massive slope collapse brought down tons of limestone onto the west side of the quarry.
MSHA required the Citizens’ Alliance to file a federal Freedom of Information Act request to obtain that order, which was delivered Feb. 24.
In that order, the agency barred mine workers from the quarry “until it is safe to resume normal mining operations.” The agency also called on RMI to submit a “written plan to recover the benches and face stability in the quarry.”
In the ensuing months, MSHA rebuffed all attempts by the Citizens’ Alliance to learn how RMI had responded to the order.
In early November, the Citizen’s Alliance used other means to access RMI’s written plan and MSHA’s subsequent modification to its closure order. The Colorado Division of Reclamation, Mining and Safety hosts a public archive of documents for all state-permitted mining operations going back over decades.
A careful search of this archive uncovered the July 7 order.
RMI’s Eastern Production Bench Access Plan
On June 26, RMI submitted a seven-page proposal to MSHA to continue operations on the lower east side of the quarry, below the section of the highwall that did not collapse.
The company consulted with Denver-based Kilduff Underground Engineering to determine “safe working clearances and procedures.” Kilduff created a simulated rockfall model that showed how far a new slide would extend if a similar slope collapse occurred on the east side highwall.
The company sought MSHA’s permission to build a six-foot safety berm across most of the width of the quarry, below the modelled rockfall runout zone. Below the berm, workers would load sellable products into trucks, moved stockpiled rock to lower benches and move its crusher machinery closer to the main mill building.
RMI also asked for MSHA approval to work temporarily above the safety berm, within the modeled rockfall runout zone, in order to retrieve a stockpile of Class 4 Road Base. Workers would leave the upper edge of that stockpile in place as an additional rockfall berm.
The company included an eight-point safety plan with its proposal.
Federal, state agencies approve RMI plan as submitted
On July 7, MSHA Field Office Supervisor Gary Joseph Polson approved a modification of agency’s Jan. 19 order to allow RMI’s proposed access plan, adding no conditions or cautions. The agency also sent the access plan and approval to Colorado Division of Reclamation, Mining and Safety (DRMS).
On July 10, Amy Yeldell, environmental protection specialist with DRMS, sent a letter to RMI noting the state agency’s acceptance of the modification and approving access to the east production bench. Yeldell added this:
“The Division’s Cease-and-Desist Order for the impacted area remains in place with the exception of the areas delineated in this request. The Division would like to emphasize that great care be taken when loading trucks on the bench, especially those of off-site contractors.”
Field observations in recent months by the Citizens’ Alliance indicate that RMI is busy with the work approved by the two agencies in July, moving the crusher and hauling crushed limestone rock to customers.