MINING & ENVIRONMENTAL SERVICES
   Specializing in underground solutions

Tunnel Closure Project - Homestake Mine, Lead, SD

MES was selected as the contractor to perform the underground tunnel rehabilitation and closure of three mine tunnels in Lead, South Dakota.

The shallow tunnels, located under and adjacent to residential structures and urban streets and utilities, were backfilled with cellular concrete grout to prevent future subsidence. Due to a severe regional shortage of portland cement, MES experimented with high-flyash cellular grout slurries, and developed a new mixture which exceeded the client's specifications while allowing the project to proceed on schedule and within budget.

One tunnel underwent bulkheading and contact and formation grouting for hydrologic sealing. The grouting was performed using a circulating grout loop, using ultrafine grout materials to seal bedrock joints and the contact between the bulkhead and the adjacent rock. The grout curtain was advanced by stage drilling and progressive re-grouting.

This project required close coordination with municipal authorities and sensitivity to the residents of the nearby structures over the 3-month project duration.

Tunnel Rehabilitation and Reconnaissance - Dinero Tunnel, Lake County, CO

MES re-opened the Dinero tunnel in order to support hydrologic evaluation and examine potential sites for a bulkhead seal to stop or retard the acid water drainage entering the Arkansas River.

The tunnel initially had a severe collapse at approximately 350 feet in from the portal, resulting in a large surface subsidence feature approximately 110 feet above. The work involved setting up provisions to handle and treat excess water flows, dewatering of impounded water from behind the cave-in using a borehole and pump system, and recovering the collapsed tunnel by driving spiling and standing steel sets.

Work continued with the advancement of rehabilitation and exploration of the tunnel an additional 1900 feet. This work included the recovery and steel setting of several minor collapses, and controlled dewatering of several mine pools, with treatment of excess flows.

MES provided both professional and construction services.

Coal Mine Entry Water Sealing and Shotcreting – Bowie Mine, Delta County, CO

In 2004 MES was contracted to perform the installation services for a new polymer water sealant and shotcrete system which was being evaluated for controlling water inflows at this underground coal mine.

Water Tunnel Rehabilitation - St. John's Tunnel, Teller County, CO

In August 2003 MES was awarded the Design-Build contract for the rehabilitation of a section of the St. John’s tunnel. This project involved the challenge of rockbolting a 6' wide by 6.5' high tunnel, working around a 30" water line at an elevation is over 11,000 feet, on the south slope of Pikes Peak. MES utilized the tunnel engineering firm of Shannon & Wilson as a design sub-consultant. Work was completed in November 2003.

Water Tunnel Rehabilitation & Bulkhead Construction - Climax Mine, Lake County, CO

The Tenmile Tunnel is located on the Climax Mine property, near Leadville, CO. at an elevation of 11,000 feet. MES was responsible for extensive rehabilitation of over 5500 lineal feet of 10’ x 10’ water tunnel, including spiling and steel setting to repair of a severe collapse zone located under a tailings pond 200 feet above.

Activities included extensive installation of ground control structures; underground blasting of oversize from cave; demolition blasting of 12' thick concrete bulkhead; blasting keyway cutout for new bulkhead, construction of 18' thick concrete bulkhead with high-pressure door large enough for an underground loader to pass through, and installation of drainpipes and automated valving.

This project also required MES to coordinate with other contractors at Climax to install a new water decant structure from the surface to underground via the installation of a new raise. MES was responsible for preparing the underground area for raise boring, transport of the raise bore cutterhead, and removal of the raise bore cuttings from the tunnel. MES' underground work had to be closely coordinated with the raise boring and other work being performed for the Owner by other Contractors as part of the same project. The other contractors included: Schmueser, Yenter, Raisebore, Mountain Structures, Canberra.

Engineering functions for various parts of the work were provided by the Owner's engineering department; MES internal staff; MES's sub-consultant Dr. John Abel, P.E.; Rocky Mountain Consultants; and URS.

MES used pre-placed (2") piping through the bulkhead forms to pump the concrete to ensure that it was tight up to the top of the cavity cut-out above the bulkhead, then later used other pre-placed pipes (1") to post-grout the concrete bulkhead perimeter after allowing two weeks for concrete shrinkage. This provided a tight seal at the floor, ribs, and back.

This work began as an unplanned emergency repair in September, 2001 and was completed through severe winter conditions at 11,000 feet in time for spring runoff in May, 2002.

Mine Tunnel Repairs and Maintenance - Mt. Emmons (Keystone Mine), Gunnison County, CO

MES was contracted to perform timbering and cleanup of fallen ground at the 2000 Level Tunnel and the 2160 Level Tunnels in the Keystone Mine (Mt. Emmons).

Emergency Shaft Repair - Milliken Shaft, Homestake Mine, Lead, SD

MES was called  to conduct recovery of the mine's ventilation after rockfall debris accumulations at the base of the Milliken shaft blocked off most of the mine's ventilation. MES provided and operated a remote-controlled 1-yard LHD unit to muck the debris clear. Incidental work included dismantling and caging the LHD to the 3500 level, reassembling the unit, scaling and roof fall cleanup from the shaft station to the work area, mucking the shaft clear, and demobilizing.

Water Tunnel Repairs - Yak Tunnel, Leadville, CO

MES was called in to perform and document an annual inspection and conduct repairs to timber in the Yak Tunnel. This is a high altitude Superfund site, located at approximately 10,500 feet.

MES was awarded a multi-year tunnel maintenance services contract for repairs planned in 2003, 2004 and 2005 via the Res-Asarco Remediation Trust Fund.

Mine Tunnel Rehabilitation - Reynolds and Chandler Adits, Summitville Mine Site, Rio Grande County, CO

MES had a three-year services agreement to US EPA prime contractor for seasonal underground mine maintenance, Reynolds and Chandler mines, Summitville Mine Superfund site.

Activities included removal of sludge, debris and muck from underground workings; Replacment of walkways and timbering as needed; Repair of pipelines from plug to portal, and repair/replacement of valving and pressure transducer.

Work was at high altitude in a very remote area.

MES' tunnel rehabilitation project at the Summitville Mine required teamwork and coordination with the prime contractor, CDM Federal Programs, Colorado Department of Public Health and Environment, US EPA, other subcontractors, and Rocky Mountain Consultants.

Underground Mine Rehabilitation, Mary Murphy Mine, St. Elmo, CO

MES completed 3 summer seasons of underground mine rehabilitation for the Colorado DMG, ending in late fall of 2000. The EPA and USFS-funded project involved re-opening the collapsed tunnel workings in an underground gold mine in a very remote, high elevation site above St. Elmo, Colorado. The work was for the purpose of ascertaining the feasibility of installing underground water control and/or diversion mechanisms to limit acid and metals releases from the mine.

On the 1400 level, MES cleaned up areas of fallen ground to facilitate access for water sampling On the 700 level reopening and support of a portal through a 60' long talus zone was required, as well as installation of track and utilities, extensive re-timbering and recovery of the tunnels in areas of fallen ground.

This high visibility project required extensive public contact on a daily basis as hikers passed through the work area.

New Decline Tunnel Installation - Glenwood Caverns, Garfield County, CO

MES provided survey, design and construction for surface excavation of a road and tunnel portal cut and an underground decline tunnel to provide tourist access to these historic caves above Glenwood Springs.

MES had to Drill & Blast about 160 feet of 8’x 8’ tunnel to access the cave. Underground and surface rock bolting and rockfall netting for the tunnel portal was also provided. Drilling and blasting was complicated by very challenging open karst cavities in the high-angled limestone beds, the location of the site above I-70, and the need to protect fragile cave formations from blast damage.

To facilitate the latter, MES constructed a set of airlock doors in the tunnel so that there would not be a rapid change of moisture or temperature when we prior to breakthrough into the caverns.

Vertical Shaft Bulkhead - Last Dollar Shaft, West of Alma, CO

MES designed and managed a project to close an 800’ deep mineshaft on a county roadway on Aspen Mountain. MES designed and installed a 28’ concrete plug to close the shaft and allow heavy truck traffic over the shaft collar. Work involved construction at approximately 11,500 feet under late fall conditions, with snowstorms during construction. Underground work was performed by personnel hanging from ropes to create hitch in rock, form and pour steel reinforced high-early strength concrete bottom form for later plug pour. Installation included drain system and subsidence monitoring stations.

Vertical Shaft Bulkhead – American Shaft at London Mine, W. of Alma, CO

This project included the underground shaft collar stabilization and polyurethane foam grouting of the American shaft at the London Mine near Alma, Colorado. The purpose was to effect both a safety closure and to retard groundwater ingress and provide shaft collar stabilization and closure. Working at over 11,000’ elevation, MES’ crew hung from ropes to stabilize or remove rotten shaft cribbing, stripped ladders and landings, installed a bottom form and steel dowels into the shaft ribs, installed a 40-foot thick vertical polyurethane foam shaft plug to seal off water ingress at the colluvium/bedrock contact.

Mine Site Cleanup & Underground Tunnel Rehab - Grace Mine, Empire, CO

MES performed environmental reclamation at numerous core drilling sites which included preparation of reclamation plan, road and drillpad obliteration and revegetation, sampling and removal of oil-stained soils as manifested special waste to permitted facility. MES re-opened underground mine workings and converted them to core storage facility for property owner. This was a mountain site north of Empire, Colorado at approximately 10,500 feet.

Mine Shaft Pump Replacement - Helena Shaft, Lake County, CO

MES was contracted to perform services to replace the pump system in the Helena Shaft at the Black Cloud Mine.

Mine Headframe Stabilization Study - Gold King Mine, Teller County, CO

MES was contracted to evaluate the options for stabilizing this historic headframe, and provide alternatives and estimated construction costs.

Mine Site Pond Dredging - Urad Mine, Clear Creek County, CO

MES was contracted to perform dredging of sediment from mine water treatment ponds, utilizing a barge and suction system.

Underground Mine Shaft Re-Collar – Chase Mine, Gilpin County, CO

MES was the Design-Build contractor for the installation of a new steel-lined shaft collar. The collar was assembled in prefabricated sections, and then concreted into place.

Water Tunnel Repair - Rio Grande Tunnel, Buena Vista, CO

Using ASI labor crew and materials, MES provided a mining engineer and its shotcrete equipment for a month to perform, lead and train ASI personnel in shotcrete nozzleman duty.

Underground Mine Rehabilitation - Gold Bug Mine, Gunnison County, CO

MES performed spiling and steel set installation for recovery of underground drift workings in remote, high altitude gold prospect. MES held a 12.5% equity position in the project in lieu of profit and managed the project on a cost-reimbursable basis.

Rehabilitation and Reinforcement - Headlight Mine, Boulder County, CO

MES performed the recovery and reinforcement of a gold mine adit portal and performed rehabilitation of the underground workings to convert the facility to an alternative use.