Colorado Division of Reclamation, Mining, and Safety

DRMS staff often pair up with other environmental protection professionals to survey areas of past mining activity for potential projects. Recently, Division and US Forest Service staff paid a visit to the Whale Mine site in Park County’s upper Hall Valley as part of such a survey.

Culverts with Grates are probably one of the most prevalent abandoned mine closure types that the DRMS installs. When the area around a mine opening is eroded and unstable, but you want to maintain access to the workings behind it, using a long length of metal culvert with a grate attached at one end can be the ideal solution. The open end of the Corrugated Steel Pipe (CSP) is placed deeper into the mine opening, into more competent rock, and then the slope around it is filled in with rock and soil. This can allow the area around the mine opening to be less hazardous, removing steep, unstable slopes. It also allows the disturbance caused by the mine opening to be filled in and naturalized, reducing its impact on wildlife, livestock, and recreation use. The grated end of the culvert can allow access to bats and for water quality monitoring, for example.

These photos show a contractor installing the bulkhead around a CSP closure on Monogram Mesa, in Montrose County; and an in-progress installation of another CSP on nearby Atkinson Mesa, north of Nucla.

Historic mining sites that present dangers to the public are spread across the country. Our fellow Abandoned Mine Reclamation Program in Utah is promoting their “Stay Out, Stay Alive” campaign to let folks out in the Beehive State know that old mine sites can be dangerous, and should be left alone. No matter where in the west your adventures take you, please stay away from abandoned mine openings! Check out the report here for more info:

https://www.fox13now.com/news/local-news/tooele-county/stay-away-state-relaunches-program-warning-of-dangers-of-utahs-abandoned-mines?fbclid=IwdGRzaAQm-X9jbGNrBCb5PWV4dG4DYWVtAjExAHNydGMGYXBwX2lkDDM1MDY4NTUzMTcyOAABHrPe8UwwFJ5V-szhq1AwOcHTQHLCJCb1jGlKyGpicxhF3krsvVaBckz6q45f_aem_au1R0XHxxQNNE0o8Y6lYfg

Stay away! Program warning of dangers of Utah's abandoned mines relaunched With an estimated 10,000 hazardous abandoned mine openings, state officials have relaunched a program to warn the public about the risks of going inside what many think would be an adventure.

Women have long worked alongside men in the mines of Colorado. Here, A woman miner, right, works alongside a male counterpart on a pneumatic drill in the Henderson Mine around 1980.

Before and after: Safeguarding inactive mine sites is an ongoing process! DRMS staff regularly visit previously-reclaimed and safeguarded sites to make sure hazards are still behind bars, filled in, or otherwise closed up. This uranium mine site near Hieroglyphic Canyon, near the Uravan townsite, is a great example.

In the first image you can see a prior safeguarding efforts, made by the mining company with relatively flexible and thinner metal grating. This was then cut away during later reclamation work (second picture). This initial barrier was completed decades before the later heavy metal grating and bat-ladder door put into place by DRMS, seen in the third picture.

There are many reasons to replace old barriers like this one: they can rust out or become dislodged as the portal's rock erodes away; vandals can cut into or otherwise compromise the barrier; and a better understanding of the ecology in and around the site could lead to more wildlife-accessible barriers.

Regular site visits are an important part of any safeguarding project's life cycle!

Historically, mining activity took place wherever there was the potential for good ore. Over time, ownership of the land on which operations took place often changed hands — inactive mines in Colorado rest on a mix of lands managed or owned by different state or Federal agencies, as well as those that are privately-held. The DRMS works in partnership with all of these entities as needed to make sure inactive mined lands are kept safe and returned to beneficial use. Here, staff from the US Forest Service, the DRMS, and the Environmental Protection Agency perform a site visit at the Garibaldi Mine.

One of the more high-tech closure materials is Polyurethane Foam (PUF). PUF is often used to plug shafts. A two-part liquid mixture is combined on-site, causing a bubbly, foamy liquid to expand into the void in which it is placed. Once the PUF has set, it becomes rigid, and can hold a substantial amount of weight. The top of the PUF plug is always set below-grade, with the area above it backfilled with topsoil which is then revegetated. Often, if it wasn’t for the project’s brass cap denoting the closure’s location, you might not even notice there had been a dangerous hole there.

Shaft and Stope Grates look pretty imposing when you come across these types of mine closures. These complex, large pieces of metalwork are placed horizontally or diagonally across vertical or near-vertical openings, with heavy metal grating is secured onto the sides by structural steel beams, concrete, or other engineered supports. The closures are designed to handle substantial weight, as they often are surrounded by steep cliffs and slopes that can shed heavy rocks and debris on to the grate, or are investigated by curious wildlife and humans.

Cable Nets: no, this isn’t a television network term...it’s another type of closure the DRMS Inactive Mine Reclamation Program puts to use in hard-to-reach places. Imagine a chain link fence made out of thick, braided steel cables and secured with heavy metal fittings. That’s a cable net!

This type of closure is often used in remote areas, where it can be hard to bring heavier, more rigid, metal frames and grating to secure a mine opening. They can be transported in by pack animals or people, up narrow trails where vehicle access is hard or nonexistent. The cliff-side uranium and vanadium workings near Nucla and Naturita have many of these sorts of closures, for example.

How are Contractors selected for reclamation projects?

The Division of Reclamation, Mining, & Safety is a state agency. As such, it uses Colorado’s standardized procurement processes to contract with businesses to assist with reclamation, safeguarding, subsidence, and other work on projects. The process is competitive, and selections are determined by cost, relevant experience and expertise, and other factors.

Since each project is unique, there is no "typical" contractor for inactive mine closure work. Many are smaller, family-run businesses who have done work like this for generations — some have been working on Division projects since the state began safeguarding old mines in the 1980s. Others are large corporations with extensive resources and world-wide expertise in reclamation, imaging, or engineering.

Project costs vary between $1,000 for a simple backfill closure, to complex shaft grates which can run $25,000. Most of these costs are paid to the contractors who do the work, who in turn put that money to work in their local towns and regions.

We value the expertise, ingenuity, and perseverance our project contractors bring to each site. We literally couldn’t do our job without them!

A decades-old coal refuse fire near Florence, CO has been fully extinguished and reclaimed. Crews excavated, quenched, and restored over 164,000 cubic yards of material, followed by regrading and native revegetation across a 9.5-acre site. This project represents a successful, science-based approach to mitigating legacy coal impacts while supporting long-term environmental stability.