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The Colorado Mining Association (CMA), the Colorado Mined Land Reclamation Board (CMLRB), and the Colorado Division of Reclamation, Mining and Safety (CDRMS) sponsor an awards program to annually honor outstanding reclamation of coal mines and further the collection and dissemination of information about successful reclamation techniques.  Four coal mining operations were recognized with Reclamation Awards in 2014

Contemporaneous Reclamation- Trapper Mining, Inc. - Trapper Mine 

 

 

The Trapper Mine was honored for its accomplishments in contemporaneous reclamation.  From 2006 to 2012, Trapper Mine has been given approval for Phase III bond release on 1,391.3 acres of reclaimed mine land.

The Trapper Mine is a surface coal mine located 6.5 miles south of the town of Craig, Colorado.  The Trapper Mine extends across the northern slope of the Williams Fork Mountains between elevations of 6,500 ft. and 7,800 ft.  The crest of the Williams Fork Mountains forms a long ridge extending east/west. The Yampa River flows generally from east to west a short distance north of the permit area.  The Williams Fork River skirts the south side of the mine site and flows into the Yampa River one mile west of the mine.  Given the steep topography of the site, both mining and subsequent reclamation presents notable challenges.  The ultimate goal of reclamation at the Trapper Mine is to return the affected land to productive use.  The approved post mine land uses for the Trapper Mine is rangeland for grazing and wildlife habitat and also cropland.  A summary of the reclamation process is below.

After removal of all coal seams which can be economically recovered, the pits at the Trapper Mine are backfilled with spoil (overburden and interburden) and then graded by dragline and dozers.  As a dragline removes overburden and interburden, spoil ridges are created by dumping the material from a recently open pit into a recently mined-out pit.  Dozers and graders then smooth the spoil ridges and blend the ridges into the existing topography.  For cropland areas, a drag is pulled over the regraded spoils to provide a smooth surface to replace topsoil; if rocks are present that will interfere with topsoil placement and tillage they are removed. After final grading of the spoil ridges, topsoil is placed on the spoil to a depth of about 18 inches on cropland and 12 inches on rangeland.  Areas are then seeded with a specific seed mix, depending on the elevation.  Range site A and B seed mixes correspond to the highest elevations within the mine site; range site C seed mix is for the lower elevations.  Cropland reclaimed parcels occupy the lowest elevations and are seeded to alfalfa and pasture grasses. The A and B range sites use the same seed mix which contains various grasses, forbs and shrubs, while the range site C seed mix contains only grasses and forbs.  Shrub clumps of approximately 1.6 acres are established from the transplanting of mature shrubs retrieved from the advancing areas of the pits.  Seeding is done by both drill and broadcasting methods.  Once reclamation is complete for a given parcel of land, Trapper monitors these areas and conducts erosion control and weed management as needed to ensure the land remains stable and the desired vegetation establishes and is productive.

In order for affected land to be approved for Phase III bond release, an operator must demonstrate that they have completed backfilling, regrading, drainage control, established vegetation that supports the approved postmining land use and that they have successfully completed all surface coal mining reclamation operations in accordance with the approved reclamation plan.   As indicated above, between the years of 2006 and 2012 Trapper Mine has obtained final Phase III bond release on 1,391.3 acres through the approval of the following bond release applications; SL7, SL10 and SL13.  These areas include 1,205.8 acres of reclaimed rangeland parcels that were graded, topsoiled and seeded from 1987 to 2001 in the Ashmore, Colt, Derringer, Enfield, Hawking and Flintlock Pits.  Also included is 185.5 acres of croplands that were reclaimed from 1993 to 1994 in Ashmore, Browning and Colt pits.  For the reclaimed cropland areas, Trapper Mine demonstrated that the alfalfa/grass hay established exceeded the production found on adjacent lands.  For the reclaimed rangeland sites, Trapper has demonstrated that the plant species established supports a remarkable amount of wildlife species such as mule deer, elk, pronghorn, Columbia sharp-tail grouse, many raptors and a variety of small birds and mammals and waterfowl.  Reclaimed rangeland sites are also managed for grazing by livestock.

Trapper Mining has diligently conducted contemporaneous reclamation on previously mined land and obtaining approval for Phase III bond release is a testimony of their faithful commitment to mine land reclamation and is worthy of recognition. 

Excellence in Minimizing Adverse Impacts of Coal Mining- Bowie Resources, LLC - Bowie No. 2 Mine

Upper Flume on West Fork of Terror Creek 

 

The Bowie No. 2 Mine was recognized for its efforts in minimizing disturbance to the hydrologic balance, minimizing adverse impacts on fish and wildlife, and preventing the adverse modification of critical habitats of threatened or endangered species.

The Bowie No. 2 Mine is an underground operation located five miles east of the town of Paonia, in Delta County, and is operated by Bowie Resources, LLC (BRL).  The mine produces approximately 3.5 million tons of coal annually.  BRL was recently awarded the Spruce Stomp federal coal lease.  As part of the permitting process with the US Bureau of Land Management (BLM) and the Division, BRL was required to obtain baseline hydrologic data for the West Fork of Terror Creek.  The West Fork of Terror Creek has been identified as potential habitat for the Greenback Cutthroat Trout, a threatened species.

In order to obtain the required baseline hydrologic data, BRL needed to install two low-flow flumes.   The flumes required approval by the Division in coordination with the BLM, US Forest Service (as land manager), US Fish and Wildlife Service (USFWS), US Army Corps of Engineers (USACE), and Colorado Parks and Wildlife (CPW).  In consultation with CPW and USFWS, the flumes were designed to prevent interference with the annual migration of fish returning to spawning areas.  Equipment used for the flume construction was disinfected prior to construction to prevent the spread of aquatic nuisance species and fish parasites.  Comments from CPW resulted in the Division requiring that instream disturbance for construction of the flumes not take place during spawning season (June 15 – Sep 1) and not exceed five days in duration.

Runoff in the spring of 2014 was later and higher than normal, causing a significant delay in starting the project.   When flows finally dropped low enough to effectively divert the creek, BRL’s contractor worked around the clock for seven full days, beginning with construction of the creek diversion channels adjacent to the creek and finishing with regrading, topsoil replacement, and seeding the disturbed area.

Construction work on the flumes was observed by Division personnel June 9-11, 2014.  Flow in the creek had been diverted around each of the construction areas.  During construction of the flumes, the diversion channels were lined with heavy plastic sheeting to prevent bed scour and entrainment of suspended solids; turbidity through the diversions appeared to be minimal.

Within 24 hours of flume construction, the stream was returned to its original channel.  Visual observations in and below the construction section the morning after flow was returned to the channel indicated that turbidity was low.  The diversion area and disturbance areas were backfilled, topsoil was replaced, and the area was seeded and mulched within 24 hours of returning the creek to its original channel.  In-stream disturbance took place within the five day maximum window allowed by CPW.  Both flumes were constructed with minimal impacts to fish and wildlife and the hydrologic balance.

Drainage Reestablishment - Seneca Coal Company, LLC - Yoast Mine

Yoast Mine Reclaimed Drainage 

Seneca Coal Company, LLC (SCC) was honored for reconstruction of permanent drainages at the Yoast Mine.  The Yoast Mine is a reclaimed surface mine in Routt County.  The elevation is approximately 7500 feet and slopes are steep.  This area is subject to heavy winter snowpack and high intensity thunderstorms in the summer months.  SCC experienced slope instability and erosion of permanent drainages following the winter of 2010-2011, when the area experienced excessive snow accumulation.  Several previously stable permanent drainages suffered downcutting and scouring following snowmelt in 2011.  SCC reconstructed these drainages in accordance with the approved permit plans, only to experience additional damage in 2012 and 2013 following high intensity thunderstorms.  In 2013, SCC reconstructed the damaged portions of the drainages, adding additional rip-rap and rock gabions to supplement the permit design requirements.  SCC reconstructed and enhanced several major drainages at the site that have held up well during the 2013 and 2014 thunderstorms and snow melt.  SCC is recognized for making the extra effort to ensure that these permanent drainages remain stable as the mine approaches its final bond liability period.

 

 

 

Landslide Remediation - Mountain Coal Company, LLC - West Elk Mine

Mountain Coal Company, LLC (MCC) was recognized for their efforts in the remediation of a native landslides adjacent to their RPE refuse pile haul road.  These landslide areas, called “HR-1” and “HR-2”, were first mapped more than 50 years ago by the U.S. Geological Survey, along with several other areas to the east and west on the north- facing mountain slopes along State Highway 133 and the North Fork of the Gunnison River.  These landslide areas have long plagued CDOT with annual landslide and mudflow debris clean-up and highway repairs, some of which cost several million dollars to complete.  The HR-1 landslide was not only perched above SH133, it also impacted MCC’s permitted stormwater drainage ditches and haul road routes upslope to the south.  Rather than just stabilize and repair only those portions of the slides that had or could impact the drainage ditches and haul road, MCC chose to complete landslide mitigation and reclaim the entire area over a three-year period at a cost of nearly $3 million.

The HR-1 landslide was first observed in May 2011 when cracking, and visible bulges distorted the native slopes below the trail pioneered for the new refuse area haul road.  Within a couple of days, the slide was roughly 400 feet wide and 300 feet high with an approximate area of three acres. The toe of the slope came to within approximately 100 feet of SH133.  A well-defined head scarp developed at the top of the slide, where a thick sandstone bed became exposed.  There were many areas where water was actively seeping out of the colluvial slide material, with very large (truck-sized) boulders “floating” down and out of the wet soils.

Through the summer of 2011, MCC worked to open up, drain and dry the slide mass.  Trenches and plastic drain pipe were installed to carry water off of and away from the slide area.  MCC consulted with contract geotechnical engineers to develop designs for the stabilization and repair of the landslide.

By December of 2011, the entire HR-1 landslide had been excavated and a filter blanket of 3/8” minus rock had been placed under the slide area, below all of the identified seeps, and up the slope to the top of the reconstructed mountain slope.  Although the design called for a filter blanket that was three feet thick, West Elk chose to construct a five foot thick filter blanket to allow for contamination of up to one foot on the top and bottom of the blanket. The purpose of the drainage design was to intercept water coming from the seeps and allow it to flow down the filter blanket, into a system of ditches and into the RPE sediment pond.  During this time, MCC simultaneously cleaned up the slide materials that continued to move toward the highway by removing the large float rock and vegetative debris and recontouring the slopes.

Unfortunately, in January 2012, another segment of the landslide broke loose to the west of the first, larger HR-1 landslide (the HR-2 landslide) and created more instability above SH133.  To remediate this new slide, MCC installed a French drain system to also intercept groundwater drainage in this area and divert it to the RPE sediment ponds.

The drains were installed and the landslides restabilized by June of 2012.  The area was then reseeded and blanketed with erosion control mats.  The landslide mitigation measures installed allowed drainage to flow onto the filter blanket, down the slope where it was intercepted by a large slotted pipe covered with pea gravel.  This pipe directed flow into the RPE sediment pond.

Another unfortunate circumstance occurred when heavy wet snows fell through the winter of 2012-2013.   These snows saturated the erosion control blankets, causing them to slump down the slope, dragging the surface soils and seed with it.  As a result, MCC again regraded the slopes and rather than blanketing them again, contracted with a hydroseeding firm to hydroseed and lightly hydromulch the slopes after straw wattles were installed across and down the slope to intercept and prevent sheet flow erosion.

This application was successful over most of the slopes and new vegetation finally became established in 2014.  MCC also continued to address small, isolated slumps and drainage issues through the summer of 2014, but the HR-1 and HR-2 landslides as a whole remain stable.