Andesite quarry to become latest county open space

By Greg Lowell Redstone Review

BOULDER COUNTY – On Route 7 heading west out of Lyons there’s what looks like a Martian landscape of reddish dirt and terraced terrain in a huge amphitheater topped by a piney ridge. Few people realize that they’re looking at what will become in a few years Boulder County’s latest open space property.

The former andesite quarry is currently being restored from its former mining operation with major grading and revegetation completion expected later this year. Once the quarry is fully stabilized and restored in a few years, Boulder County Parks & Open Space will devise a management plan with public input that is expected to preserve unique plant and wildlife communities while allowing public recreation where appropriate.

BCPOS purchased the 568-acre property in 2011 for the purpose of preserving its open space values. BCPOS paid $12,770,000 for the property.

70-year mining ends, reclamation starts

Andesite mining at the site started some 70 years ago. The gray volcanic rock is primarily used in construction. The Hall family – a longtime presence in the Lyons area – owned the land and leased the quarry to the operators Aggregate Industries and now Holcim-WCR, Inc.

All mining there ceased in 2008. Under the terms of a permit granted by the Colorado Division of Reclamation, Mining and Safety the site must be restored to its previous condition. The operators were granted reprieve by DRMS which allowed them to postpone activities on the site and delay restoration until 2016. They then would have five years to complete the work.

But the reclamation work was delayed as a result of the impacts of the 2013 flood, which washed out the county bridge across South St. Vrain Creek and the access road to the site. The bridge and access road were repaired in 2017, but the project was postponed yet further due to revisions to the reclamation design and COVID-19 issues. Work was finally started in fall 2021.

Although the property is now owned by Boulder County, all reclamation work and DRMS requirements are the responsibility of the previous mining company. BCPOS staff has worked with the mining company since the property was purchased to ensure the reclamation project meets the county’s open space interests to the extent possible.

Of note, Boulder County worked with the mining company to preserve a portion of the exposed dacite, which is a type of granite. Geologists believe the dacite is the terminus of the “mineral belt” that spans from southwest Colorado to Lyons and was retained for educational purposes.

County will wait for reclamation

Grading and revegetation of the site is nearly done. Once completed, however, the mining company must monitor and maintain the site for several years. Before the reclamation is approved by DRMS, the land must be revegetated and stabilized, and the vegetation must be able to self-generate without need of fertilizer or irrigation.

Only when the mining company has satisfied the reclamation requirements will BCPOS take over management of the entire property.

River work also slated

In separate work, the South St. Vrain Creek, which comprises the northern boundary of the quarry, will be restored back to its original natural course. The creek was moved and channelized many years ago, taking it away from its natural floodplain.

Returning the river to its natural alignment will improve resiliency by increasing the floodplain connectivity and providing areas for flood waters and sediment to spread and settle out, which will benefit Lyons and other downstream communities. Habitat quality will also be improved through in-stream features, such as riffles and pools and large woody debris. Realigning the river will could also provide better access for potential future public use if allowed in the management plan.

Biodiversity, conservation, recreation water resources than just digging a hole.

The site, now designated as Hall Ranch 2, runs from the South St. Vrain Creek up steep, rugged terrain to the ridge behind it that borders Heil Valley Ranch Open Space.

So first I clear a promising area and level it. Then I wander the land looking for stones to build a revetment. That’s a fancy word for a little wall that will hold the soil and help retain moisture.

After planting and mulching I install a wire basket to keep the deer out. Yes, you can wing it and leave your arborial wards exposed to passing herbivores, but it only takes a browsing fawn a few seconds to chew off a year’s growth. I have evolved the protection system into a sort of sculptural whimsy. I start with a sheet of 2” x 4” deer wire to make a cylinder, and then add a domed top out of woven wire and hardware cloth. Forty-five minutes with a pair of pliers, and you have aching fingers, but you have crafted R2D2’s distant cousin. No it can’t translate Wookie into Mandalorian but it can communicate to the deer to chomp elsewhere.

In 2002 our cousin Jane in Omaha gave me some Kentucky coffee tree seeds like large brown lima beans. The Latin name is gymnocladus dieociae, which means something like armored seed. I managed to achieve germination and nursed the babies along and now after almost 20 years one seedling has soared to almost three feet tall: still too small to cling to but mature enough to have long conversations with. I can’t wait until she’s big enough to hug.

Peter Butler was born in India and lived in a house facing a giant kapok tree. Growing up in England there were trees but never quite enough. After qualifying as biochemist there as a gradual evolution into being a graphic designer. He and his wife Deirdre moved to the States in 1997 and to Lyons in 2000. Finally there are enough trees.

“The mine site and surrounding land support tremendous habitat and ecological values, which are related to the unfragmented and undisturbed nature of the surrounding landscape,” said David Hirt, Senior Plant Ecologist/Restoration Ecologist for BCPOS.

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