Board approves Curtwright Pit reclamation amendment over objections; orders six‑month inspections

The Mined Land Reclamation Board on Sept. 17 approved Amendment 1 (AM1) to the Curtwright Pit permit (M1986‑123), a construction‑materials permit operated by Colson Excavating Company, despite formal objections from an adjacent landowner and technical challenges raised by objectors’ consultants.

What the board decided

After several hours of testimony, technical presentations and cross‑examination, the board voted to approve AM1 over objections and added an instruction that DRMS (the Division of Reclamation, Mining and Safety) provide the board with follow‑up field inspections and a status report every six months. The vote followed a staff recommendation that AM1 satisfied applicable Mined Land Reclamation Board rules and the Act’s requirements.

Why AM1 was before the board

AM1 was filed after a board enforcement order (MB2020‑312) found mining activity had affected lands outside the then‑approved permit boundary. The amendment seeks to add 19.42 acres (increasing the permit from 77.97 to 97.39 acres), update the reclamation plan for areas affected outside the original boundary, install drainage mitigation (a swale and a slide gate at a culvert), regrade side slopes to the required 3:1 where needed, remove several stockpiles and revegetate disturbed areas. The applicant proposed a revised reclamation bond of $124,795 to cover the updated work; DRMS’ own estimate used for staff recommendation matched that figure.

Staff presentation and recommendation

Patrick Lindbergh, representing DRMS, summarized the chronology that led to AM1: DRMS inspections beginning in 2023 identified roughly 4.7 acres affected outside the permit boundary, an enforcement order followed, the operator submitted AM1 in February 2024, DRMS issued incompleteness letters and later deemed the application complete. Public notice produced about 38 letters of objection.

Lindbergh told the board DRMS inspected the site, reviewed files and concluded: (1) the amendment correctly incorporates affected lands into the permit boundary; (2) the proposed reclamation — grading, backfilling of a former pond, a drainage swale and revegetation with a seed mix similar to the previously approved mix — meets the intent of the reclamation rules (citing rule 6.4.5 and applicable provisions of rule 3.1); (3) potential impacts from flooding and groundwater depletions are addressed by the proposed slide gate/culvert control and by an existing, approved substitute water supply plan (SWSP) that dedicates water shares to cover evaporative depletions; and (4) fish and wildlife concerns (Preble’s meadow jumping mouse) were considered and the U.S. Fish and Wildlife Service had previously concurred on a 300‑foot riparian buffer around the river.

Key technical and factual disputes

Objectors (landowner Linda O’Brien and consulting engineer Dan Giroux) focused on four areas: - Vegetation and soil: Objectors said the north parcel (O’Brien’s land) lacks topsoil and currently supports sparse or low‑value vegetation and noxious weeds following floods, so seeding without imported or reconditioned topsoil is unlikely to succeed. DRMS and the applicant said historical aerials and past inspections showed the area once supported dense vegetation and that the plan’s seed mix and mechanical site preparation should succeed. - Side slopes and the “land bridge”: Objectors and their engineer said multiple pond side slopes are steeper than 3:1 and that grading will be more extensive than the applicant’s maps indicate; they raised concerns about erosion, wave action and the stability of an access land‑bridge used by the landowner to reach the north parcel. The applicant’s consultant said most slopes are already 3:1 or vegetated and that regrading in identified areas is both feasible and limited in scope. - Flooding and the drainage swale: Objectors questioned whether the proposed swale and a slide gate on a culvert would reliably evacuate floodwater given very low site slopes; applicant and its hydrology consultant said HEC‑RAS modeling based on recent events shows the mitigation will reduce nuisance flooding, and the slide gate design (including optional flap gates) would give the landowner ways to drain the site after floods. Objectors’ hydrologist recommended a more detailed two‑dimensional overbank model and expressed concern that the proposed alignment and very shallow slope may not perform in all conditions. - Water for exposed groundwater and bonding: The applicant filed an approved substitute water supply plan that dedicates water shares to cover evaporative depletions; DRMS and the applicant argued the dedicated shares and approved SWSP meet Division of Water Resources guidance for bonding. Objectors argued the bond should be large enough to cover alternative measures (for example, pond lining) if permanent augmentation is delayed or not obtained; DRMS said additional surety would be set through a future technical revision only if the operator proposes such an alternative and that the division’s bond calculation follows statutory and rule limits.

Other evidence and process notes

- The applicant (Colson Excavating) presented engineering and water‑rights experts, and attorneys explained the status of water‑court case 19CW3157 that seeks permanent augmentation; the applicant’s water‑engineering expert said the portfolio of water supplies (Hillsborough shares, Big Thompson & Platte River ditch shares and municipal leases) appears sufficient and that ongoing work aims to finalize the water‑court adjudication in the coming years. - The objectors presented a wetlands/vegetation assessment and argued that site photos and field measurements show persistent mudflat conditions and poor forage value on the north parcel; they urged that imported or proven topsoil and clearer grading instructions should be required to ensure success.

Board action and conditions

The board approved AM1 over objections and added a discrete reporting requirement: DRMS was instructed to perform field inspections and report back to the board every six months on implementation progress and any unresolved issues. The board did not adopt a competing technical requirement (for example, mandatory importation of topsoil or a specific lining contingency) at the hearing; instead it relied on DRMS’ determination that the amendment met rule requirements and on the board’s ability to review release/reduction requests and future technical revisions if performance problems recur.

Why it matters

The amendment resolves a long‑running enforcement matter by explicitly bringing affected lands into the permitted boundary, updating the reclamation plan to address disturbed areas, and setting a path for corrective earthwork, drainage mitigation and revegetation. Objectors retain procedural rights: DRMS must notify landowners and counties before any surety release, and the landowner or other interested parties may submit objections if and when the operator requests financial‑warranty reductions or final release. The board’s six‑month inspection requirement creates a near‑term check on progress and gives the board regular updates for future oversight.

Next steps

DRMS will track implementation and supply the board with six‑month inspection reports as requested. The operator may proceed with the field work required by AM1 under DRMS oversight and must follow the division’s procedures if it later requests reduced surety or final release. If the permanent water‑court augmentation is not achieved, the operator and DRMS retain options (including additional amendments, pond lining technical revisions, or revised surety calculations) to achieve an acceptable long‑term solution.