Environmental Impacts of Pit Mining

Save Our St. Vrain Valley (SOSvv.) proclaims the right of self-governance in matters that directly affect the people and the environment in which we live. We assert our community’s right to clean air and pure water; the rights of ecosystems to thrive; the right to peaceful enjoyment of this unique place by residents and visitors; and the importance of conserving the last largely undeveloped mountain river valley leading from the Front Range onto the Great Plains.

The proposed mining project west of Hygiene would negatively impact the environment here for up to twenty years during active mining and reclamation, and possibly much longer. In “Environmental Impacts of Mining Natural Aggregate,”1 William Langer and Belinda F. Arbogast state, “We cannot obtain aggregate resources without causing some environmental disturbance. Some of the disturbance is caused directly by the mining or processing activities. The most obvious environmental impact of aggregate mining is the conversion of land use, most likely from undeveloped or agricultural land use, to a hole in the ground. This major impact may be accompanied by loss of habitat, noise, dust, vibrations, chemical spills, erosion, sedimentation, changes to the visual scene, and dereliction of the mined site” (153).

To the immediate southeast of Lyons the cement plant and other mining operations have already disturbed the bucolic beauty of the St. Vrain Valley, visually impacting portions of the landscape and adversely affecting the environment. In the case of the cement plant, which is due to close in 2021, the previous owner Cemex recently paid a $1 million civil penalty and was required to install $600,000 worth of pollution control equipment at the plant to settle alleged violations of the Clean Air Act. It is worth noting that the impetus for this did not initially come from local, state, or federal agencies, but from the St. Vrain Valley Community Watchdogs, a group of citizen activists who worked diligently to preserve the health of people and the environment in the area. The collaborative work of the Watchdogs, several of whom are active members of SOSvv, with the Boulder County Health Department earned Boulder County a prestigious award from the National Association of Counties for its effort to make the region around Lyons and the St. Vrain River cleaner and healthier.

Sand and gravel mining sites from the past and present, some reclaimed and some still unsightly large swaths of barren dirt, are visible in some areas around St. Vrain Creek between US 36 and Hygiene Road. Most of the ponds we see here are the result of pits filled by groundwater at the conclusion of mining. The mining industry views these as positive outcomes. But these are not natural formations, and their presence alters the balance of this ecosystem. In fact, they seem to have exacerbated damage caused by the 2013 flood. For example, the 2014 St. Vrain Creek Watershed Master Plan [PDF] notes, “During the flood, large split flow paths cascaded through the reclaimed gravel mining ponds. One split channel resulted in flooding outside of the 100-year floodplain and affected neighborhoods downstream in the City of Longmont” (3-2).

The county permits governing these industrial activities do include reclamation plans, but despite any assurances from the industry, reclamation simply cannot restore the land to its natural or pastoral states prior to mining. Langer and Arbogast state, “Restoration to the original condition is seldom possible because we do not currently have the level of information and skill required to return ecosystems exactly to their original structure. In addition, the new land is environmentally unstable, and exotic species invade disturbed sites. Many native organisms do not return or fill the same ecological niche” (163). A related point to consider is that, for various reasons, reclamation may not occur within projected time frames.

The land proposed for imminent mining (to the west of 61st and 63rd streets between Hwy 66 and Hygiene Rd) is a patchwork of properties owned by both Martin Marietta Materials, Inc. and Boulder County as part of its Open Space holdings. Is Boulder County leasing the mining rights to Martin Marietta? Do citizens in the area truly have a say in this matter, or is the January 3, 2017 Boulder County Commissioners meeting an indication of the community’s actual role in the process, where the site plan was issued without a public hearing and without adequate notification of the residents who would be most severely impacted? Is the Citizens Advisory Group described in the permit, to be formed only a month before mining commences, a largely symbolic gesture in what is ultimately a foregone conclusion?

The Boulder County Comprehensive Plan (BCCP) addresses various land use issues, and includes information relevant to this proposed mining project. Links to the numerous maps in the plan are also provided on the BCCP website. The BCCP Geologic Hazard and Constraint Areas Map designates the majority of the proposed mining area as a “Geologic Hazard Area,” with a “Moderate” risk of flooding. The Geology Element of the plan states, “Geologic hazard shall mean a geologic condition or geologic process which poses a significant threat to health, life, limb, or property,” and “Moderate Hazard Area shall mean that area, or those areas, as shown on the Geologic Hazards and Constraint Areas Map where geologic conditions are such that significant geotechnical problems exist and there is provisional risk related to intensive land uses” (Geology [GE] – Page 1). Notably, GE 1.02 states: “The county shall discourage intensive uses in Moderate Hazard Areas.”

Visit our additional pages on environmental concerns, which address air quality; water quality and the need for flood repairs; conservation of biodiversity; and the agricultural value of this land.

1. Langer, William H., and Belinda F. Arbogast. “Environmental Impacts Of Mining Natural Aggregate.” In Deposit and Geoenvironmental Models for Resource Exploitation and Environmental Security, edited by Andrea G. Fabbri, Gabor Gaál, and Richard B. McCammon, 151–69. Nato Science Partnership Subseries: 2 (Closed) 80. Springer Netherlands, 2002. doi:10.1007/978-94-010-0303-2_8.