Am#2 Appx 1- Item 4.0 Feature Work Table REVISED.pdf
PDF 213 KB Posted
- Attached to
- PKAA, Dream Canyon Project
- Solicitation number
- DQ1 PKAA 2026000355 4
- Issued by
- Boulder County, Colorado
About this file
This document is a Feature Work Table for the Dream Canyon Project in Colorado, outlining the specifications and closure methods for 21 mine features requiring remediation as part of Item 4.0 of the project scope. The work encompasses the closure of various mine openings including shafts, stopes, and adits with depths ranging from 5 to 100 feet. Closure methods vary by feature and include machine backfill with imported or onsite material, rock bulkheads with bat ladders, grated shaft closures with bat cupolas, and polyurethane foam plugs with corrugated steel pipe installations. Each feature is identified by location coordinates (UTM NAD83), and work descriptions specify requirements such as bat exclusion prior to closing, debris removal, rock barring, stormwater sediment control measures with biodegradable waddles, and proper disposal of timber. The project includes specialized structural work such as steel beam installations for grated closures and drainage considerations for certain features.
All work is governed by general bid specifications and drawings referenced in Sections 2, 8, 9, 10, 11, 13, and 14, with standard drawings and attachments detailing bat cupola and polyurethane foam specifications. Storm water management and environmental controls are mandatory across all features, with contractors required to implement twenty-five linear feet of biodegradable waddles on the downstream side of each working area under project manager direction. The work includes assessments for rock competency, foundation clearing, and structural engineering considerations for closures involving steel beams and bulkheads. Bid specifications distinguish between features requiring access doors and drainpipes versus those that do not, with bat exclusion and bat accommodation features integrated into multiple closure designs to maintain ecological compatibility.
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Text version
Appendix 1 – Item 4.0 Feature Work Table REVISED
Table - Dream Canyon – Item 4.0 Install Mine Closures
Feature ID Type Description of Mine
Opening Closure Method
General Bid Specifications and Drawings
UTM
(X,Y)
NAD83 Work Description / Notes
363-GF002 Shaft
Excavated:5ft by 6ft Eroded:8ft by 8ft Present:8ft by 8ft
Depth:15 ft Lining:Rock Drainage:No
Machine Backfill Section 2 465599
4428500
BAT EXCLUSION PRIOR TO CLOSING PER SPEC
PROVIDED UNDER ITEM 4.0.
Remove timber debris. Excavate to determine extents.
Bar off rocks from shaft collar and machine backfill with approximately fifty (50) cubic yards of imported common fill material. Rockfill is not required.
Storm water sediment control measures shall be implemented prior to work on the closure. Twenty-five
(25) linear feet of biodegradable waddles shall be installed on the downstream side of the working area under the direction of the PROJECT MANAGER.
363- GF002a Shaft
Excavated:5ft by 9ft Eroded:12ft by 9ft Present:5ft by 9ft Depth:23 feet ft
Lining:Rock Drainage:No
Machine Backfill Section 2 465580.
4428496
Remove timber debris. Excavate to determine extents.
Bar off rocks from shaft collar and machine backfill with approximately fifty (50) cubic yards of imported common fill material. Rockfill is not required.
Storm water sediment control measures shall be implemented prior to work on the closure. Twenty-five
(25) linear feet of biodegradable waddles shall be installed on the downstream side of the working area under the direction of the PROJECT MANAGER.
Description of Mine
Opening Closure Method
General Bid Specifications and Drawings
UTM
(X,Y)
NAD83 Work Description / Notes
363-GF003 Stope
Excavated:
Eroded:17ft by 34ft Present:17ft by 34ft
Depth:17 feet ft Lining:Rock Drainage:No
Machine Backfill Section 2 465564
4428474
BAT EXCLUSION PRIOR TO CLOSING PER SPEC
PROVIDED UNDER ITEM 4.0.
Remove three (3) mature trees and set aside below the feature to create a barrier to catch any debris that may leave the site during construction. The feature is located above Highway 119 and contractor will need to take precautions to avoid any rock/boulders rolling downhill. Excavate to determine extents. Machine backfill with onsite material. Rockfill is not required.
Cut downed trees into four (4) foot lengths and pile neatly after backfill is complete.
Storm water sediment control measures shall be implemented prior to work on the closure. Twenty-five
(25) linear feet of biodegradable waddles shall be installed on the downstream side of the working area under the direction of the PROJECT MANAGER.
363-GF004 Stope
Excavated:5ft by 7ft Eroded:3ft by 7ft Present:3ft by 7ft Depth:18 feet ft
Lining:Rock Drainage:No
Machine Backfill Section 2 465562
4428520
BAT EXCLUSION PRIOR TO CLOSING PER SPEC
PROVIDED UNDER ITEM 4.0.
Excavate to determine extents. Machine backfill with onsite material. Rockfill is not required.
Storm water sediment control measures shall be implemented prior to work on the closure. Twenty-five
(25) linear feet of biodegradable waddles shall be installed on the downstream side of the working area under the direction of the PROJECT MANAGER.
363-GF005 Adit
Excavated:3ft by 7ft Eroded:3ft by 7ft Present:3ft by 7ft Depth:18 feet ft
Lining:Rock Drainage:No
Machine Backfill Section 2 465493
4428523
BAT EXCLUSION PRIOR TO CLOSING PER SPEC
PROVIDED UNDER ITEM 4.0.
Excavate to determine extents. Machine backfill with onsite material. Rockfill is not required.
Storm water sediment control measures shall be implemented prior to work on the closure. Twenty-five
(25) linear feet of biodegradable waddles shall be
Description of Mine
Opening Closure Method
General Bid Specifications and Drawings
UTM
(X,Y)
NAD83 Work Description / Notes
363-GF006 Adit
Excavated:3ft by 7ft Eroded:3ft by 7ft Present:3ft by 7ft Depth:15 feet ft
Lining:Rock Drainage:No
Rock Bulkhead w/ Bat Ladder
Section 14 Section 13
Std. Drawing #s
6.2 & 10
465476 4428525
Construct a Rock Bulkhead closure with Bat Grate Alternative. Utilize a minimum three (3) foot length of twenty-four (24) inch, twelve (12) gauge CSP with an attached bat ladder.
Neither an access door nor drainpipe are required.
363- GF007a Stope
Excavated:10ft by 4ft Eroded:10ft by 4ft Present:10ft by 4ft
Depth:10 feet ft Lining:Rock Drainage:No
Modified Machine Backfill
Section 2 465506 4428556
Install 5 CY of polyurethane foam inside opening to support bridge. Backfill both sides of opening with onsite material. Use large rocks on site.
Storm water sediment control measures shall be implemented prior to work on the closure. Twenty-five
(25) linear feet of biodegradable waddles shall be installed on the downstream side of the working area under the direction of the PROJECT MANAGER.
363- GF007b Stope
Excavated:3ft by 5ft Eroded:3ft by 5ft Present:3ft by 5ft Depth:10 feet ft
Lining:Rock Drainage:No
Modified Machine Backfill
Section 2 465497 4428550
Install 5 CY of polyurethane foam inside opening to support bridge. Backfill both sides of opening with onsite material. Use large rocks on site.
Storm water sediment control measures shall be implemented prior to work on the closure. Twenty-five
(25) linear feet of biodegradable waddles shall be installed on the downstream side of the working area under the direction of the PROJECT MANAGER.
363- GF007c Stope
Excavated:3ft by 5ft Eroded:3ft by 5ft Present:3ft by 5ft Depth:10 feet ft
Lining:Rock Drainage:No
Machine Backfill Section 2 465492
4428546
Backfill trench and stope with large onsite rocks and material.
Storm water sediment control measures shall be implemented prior to work on the closure. Twenty-five
(25) linear feet of biodegradable waddles shall be
Description of Mine
Opening Closure Method
General Bid Specifications and Drawings
UTM
(X,Y)
NAD83 Work Description / Notes
363-GF008 Stope
Excavated:60ft by 1ft Eroded:60ft by 5.5ft Present:50ft by 5.5ft
Depth:65 feet ft Lining:Rock Drainage:No
Shaft Grate w/ Bat Cupola
Section 8, Std.
Drawing # 4 and
Attachment 3
465469 4428544
Stope ranges in width from three (3) to ten (10) feet.
Grating will span sixty (60) feet by ten (10) feet.
Install a grated shaft closure with a bat cupola in accordance with Grated Shaft Closure Specifications and Attachment 3, Bat Cupola Specifications. The modified bat gate will be a raised four (4) sided ‘cupola’ consisting of one (1), six inch (6”) high by twenty-four inch (24”) wide bat slot on each side. Approximately fifteen (15) ten-foot (10’) W4 x 13 steel beams are required, adjusted by grating sizes specified in Table
8.1 in Section 8 of the General Bid Specifications.
Incompetent, weak and failing rock will need to be barred down prior to any work. Access Door NOT required.
363-GF009 Stope
Eroded:20ft by 40ft Present:13ft by 22ft
Depth:100 ft ft Lining:Rock Drainage:No
Shaft Grate w/ Bat Cupola
Section 8, Std.
Drawing # 4 and
Attachment 3
465538 4428565
Install a grated shaft closure with a bat cupola in accordance with Grated Shaft Closure Specifications and Attachment 3, Bat Cupola Specifications. The modified bat gate will be a raised four (4) sided ‘cupola’ consisting of one (1), six inch (6”) high by twenty-four inch (24”) wide bat slot on each side. Approximately five (5), fifteen foot (15’) W6 x 20 steel beams are required, adjusted by grating sizes specified in Table
8.1 in Section 8 of the General Bid Specifications..
Access Door NOT required.
363-GF010 Adit/ Decline
Excavated:5ft by 2ft Eroded:5ft by 2ft Present:5ft by 2ft
Depth:5 ft ft Lining:Concrete
Drainage:No
Grate with Bat Grate Alternative
Section 11 Section 13
Std. Drawing #s
6.1 & 6.2
465473 4428548
Construct a grated adit closure with a minimum two (2) foot by four (4) foot bat ladder in accordance with Grated Adit Closure Specifications. Neither an access door nor drainpipe are required.
363- GF010a
Adit/ Decline
Excavated:5ft by 2ft Eroded:5ft by 2ft Present:5ft by 2ft
Depth:8 ft Lining:Concrete
Drainage:No
Rock Bulkhead
Section 14 Std.
Drawing # 10
465472 4428594
The foundation shall be cleared of all unconsolidated material prior to construction of the bulkhead.
Construct a bulkhead seal of grouted durable native rock, a minimum of thirty inches (30”) in thickness.
Drainpipe IS required. Access door is NOT required.
Description of Mine
Opening Closure Method
General Bid Specifications and Drawings
UTM
(X,Y)
NAD83 Work Description / Notes
363-GF012 Shaft
Excavated:4ft by 8ft Eroded:17ft by 35ft Present:15ft by 25ft
Depth:14 feet ft Lining:Rock
Drainage:Yes
Machine Backfill Section 2 465645
4428649
Collapse sides of opening to reduce highwall. Leave wood/brush debris. Sixty cubic yards (60cy) of imported common fill required.
Storm water sediment control measures shall be implemented prior to work on the closure. Twenty-five
(25) linear feet of biodegradable waddles shall be installed on the downstream side of the working area under the direction of the PROJECT MANAGER.
363-GF013 Adit
Excavated:8ft by 7ft Eroded:9ft by 9ft Present:9ft by 9ft Depth:17 feet ft
Lining:Rock Drainage:No
Grate with Access and Bat Grate Alternative
Section 11 Section 13
Std. Drawing #s
6.1 & 6.2
465690 4428641
After clearing all loose debris, specifically removing loose rock above the adit, Construct a grated adit closure with a minimum two (2) foot by four (4) foot bat ladder in accordance with Grated Adit Closure Specifications. Access door is required. Drainpipe is not required.
363-GF015 Shaft
Excavated:8ft by 5ft Eroded:10ft by 10ft Present:10ft by 10ft
Depth:10 ft Lining:Rock
Drainage:Yes
Machine Backfill Section 2 465714
4428570
Excavate to determine extents. Machine backfill with onsite material. Rockfill is not required.
Storm water sediment control measures shall be implemented prior to work on the closure. Twenty-five
(25) linear feet of biodegradable waddles shall be installed on the downstream side of the working area under the direction of the PROJECT MANAGER.
363- GF015a
Adit/ Decline
Excavated:4ft by 5ft Eroded:2ft by 3ft Present:2ft by 3ft
Depth:10 ft Lining:Rock
Drainage:Yes
Rock Bulkhead
Section 14 Std.
Drawing # 10
465731 4428572
The foundation shall be cleared of all unconsolidated material prior to construction of the bulkhead.
Construct a bulkhead seal of grouted durable native rock, a minimum of thirty inches (30”) in thickness.
Drainpipe IS required. Access door is NOT required.
363-GF016 Adit
Excavated:3ft by 1.5ft Eroded: 3ft by 1.5ft Present: 3ft by 1.5ft
Depth:14 ft Lining:Rock Drainage:No
Rock Bulkhead w/ Bat Ladder
Section 14 Section 13
Std. Drawing #s
6.2 & 10
465737 4428520
The foundation shall be cleared of all unconsolidated material prior to construction of the bulkhead.
Construct a Rock Bulkhead closure with Bat Grate Alternative. Utilize a minimum three (3) foot length of thirty-six (36) inch, twelve (12) gauge CSP with an attached bat ladder.
Neither an access door nor drainpipe are required.
Description of Mine
Opening Closure Method
General Bid Specifications and Drawings
UTM
(X,Y)
NAD83 Work Description / Notes
GF017 Stope
Excavated:5ft by 3ft Eroded:5ft by 3ft Present:5ft by 3ft Depth:20-30ft ft
Lining:Rock Drainage:No
Grated Corrugated Steel Pipe with Bat Grate
Alternative
Section 9 Section 10 Section 13
Std. Drawing #s 5 & 6.2
465671 4428646
Set a bottom form at a depth of ten (10) feet and install approximately eighteen (18) cubic yards of polyurethane foam in accordance with Polyurethane Foam Closure Specifications to create a plug.
Construct a 24-inch diameter ten (10) foot length of twelve-gauge (12 ga.) corrugated steel pipe (CSP) with bat ladder in accordance with Corrugated Steel Pipe Specifications and Bat Grate Alternative. A minimum of eight (8) feet of CSP will be set inside the opening. On-site materials shall be used to backfill around the CSP.
No access door or drain pipe is required.
W-1 Stope
Excavated:5ft by 3ft Eroded:13ft by 13ft Present:5ft by 3ft
Depth:N/A ft Lining:Rock Drainage:No
Machine Backfill Section 2 469855
4429753
Excavate to determine extent of opening. Backfill with onsite material. Rockfill is not required.
Storm water sediment control measures shall be implemented prior to work on the closure. Twenty-five
(25) linear feet of biodegradable waddles shall be
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