A#1_REVISED Appendix A Cottonwood Mine Closure 796.pdf

Table 1 – REVISED Aug. 12, 2026 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

CCC139 Shaft

Present: 10ft by 12ft Depth: 14 ft

Lining:

Drainage: No

Machine Backfill

Section 2.0–Backfill Closure

449127.097, 4398113.171

Machine backfill in accordance with Backfill Closure Specifications with onsite materials. No rock fill required. Storm water sediment control measures shall be implemented prior to work on the closure.

Twenty-five (25) feet of excelsior waddles shall be installed on the downgradient side of the working area.

CCC140 Adit

Present: 1ft by 1ft Depth: >50 ft

Lining:

Drainage: No

Grated Corrugated Steel Pipe with Bat Grate

Alternative

Section 10–Corrugated Steel Pipe Adit Closure Section 13–Bat Grate Alternative Std. Drawing #s 5 & 6.2

449076.158, 4397826.473

After clearing all loose debris, install a twenty four

(24) inch diameter ten (10) foot length of twelve (12) gauge corrugated steel pipe (CSP) with bat ladder in accordance with Corrugated Steel Pipe Adit Specifications and Bat Grate Alternative. Access door is not required. Drainpipe is not required. Rock grouting around the CSP is required. The CONTRACTOR shall cover the CSP with onsite soil bedding prior to backfill and to reduce the likelihood of damage to the CSP by falling rock from the brow.

In addition, the exterior of the CSP shall be backfilled using onsite material.

Feature ID Type Description of Mine Opening

Closure Method

General Bid Specifications and

Drawings

UTM

(X,Y) NAD83 Work Description / Notes

CCC141 Adit

Present: 1ft by 1ft Depth: >25 ft Lining: Rock Drainage: No

Grated Corrugated Steel Pipe with Bat Grate

Alternative

Section 10–Corrugated Steel Pipe Adit Closure Section 13–Bat Grate Alternative Std. Drawing #s 5 & 6.2

448993.355, 4397796.808

After clearing all loose debris, install a twenty four

(24) inch diameter ten (10) foot length of twelve (12) gauge corrugated steel pipe (CSP) with bat ladder in accordance with Corrugated Steel Pipe Adit Specifications and Bat Grate Alternative. Access door is not required. Drainpipe is not required. Rock grouting around the CSP is required. The CONTRACTOR shall cover the CSP with onsite soil bedding prior to backfill and to reduce the likelihood of damage to the CSP by falling rock from the brow.

In addition, the exterior of the CSP shall be backfilled using onsite material.

CCC143 Stope

Present: 21ft by 26ft Depth: 60 ft

Lining: Other Drainage: No

Shaft Grate with Bat Grate

Alternative

Section 8–Grated Shaft Closure Section 13–Bat Grate Alternative Std. Drawing #s 4 & 6.2and Attachment 3

449066.179, 4398080.585

Construct a grated shaft closure with a Bat Cupola in accordance with Grated Shaft Closure Specifications.

Poor rock condition at the collar will require six (6) concrete footers. Excavate two by two foot (2 x 2 ft) pockets with the outside edge of each pocket a minimum of four (4) feet from the edge of the opening.

The modified bat grate will be a raised four (4) sided ‘cupola’ consisting of one (1) six (6) inch high by twenty-four (24) inch wide bat slot on each side.

An access door is not required.

Feature ID Type Description of Mine Opening

Closure Method

General Bid Specifications and

Drawings

UTM

(X,Y) NAD83 Work Description / Notes

GC049 Stope

Present: 6ft by 20ft Depth: 25ft

Lining: Other Drainage: No

Hybrid Machine Backfill

Section 2.0–Backfill Closure Section 9.0 – Polyurethane Foam Closure

454458.490, 4413569.765

Install twenty (20) cubic yards of polyurethane foam (PUF). PUF will be installed in the bottom of the opening and allowed to cure for three (3) days. Then backfill the remaining opening in accordance with Section 2.0 Backfill Closure Specifications with onsite materials. Storm water and sediment control measures shall be implemented prior to work on the closure. Twenty five (25) feet of excelsior waddles shall be installed downgradient of the work area.

GC050 Shaft

Present: 3ft by 4ft Depth: ft

Lining: Other Drainage: No

Machine Backfill

Section 2.0–Backfill Closure

453305.638, 4416493.989

Machine backfill in accordance with Backfill Closure Specifications with onsite materials. No rock fill required. Storm water sediment control measures shall be implemented prior to work on the closure.

Fifty (50) feet of excelsior waddles shall be installed on the downgradient side of the working area.

GC051 Shaft

Present: 2ft by 3ft Depth: 70 ft

Lining: Other Drainage: No

Grated Corrugated Steel Pipe with Bat Grate

Alternative

Section 10–Corrugated Steel Pipe Adit Closure Section 13–Bat Grate Alternative Std. Drawing #s 5 & 6.2

455008.871, 4413061.06

Insert CSP then backfill with on-site material against exposed cribbing to stabilize. After clearing all loose debris, install a twenty four (24) inch diameter eight

(8) foot length of twelve (12) gauge corrugated steel pipe (CSP) with bat ladder in accordance with Corrugated Steel Pipe Adit Specifications and Bat Grate Alternative. Access door is not required.

Drainpipe is not required. Rock grouting around the CSP is required. The CONTRACTOR shall cover the CSP with onsite soil bedding prior to backfill and to reduce the likelihood of damage to the CSP by falling rock from the brow. In addition, the exterior of the CSP shall be backfilled using onsite material.

Feature ID Type Description of Mine Opening

Closure Method

General Bid Specifications and

Drawings

UTM

(X,Y) NAD83 Work Description / Notes

LAR009 Adit

Present: 3ft by 4ft Depth: 35 ft Lining: Rock Drainage: No

Rock Bulkhead with Bat Grate

Alternative

Section 14–Rock Bulkhead Closure Section 13-Bat Grate Alternative Std. Drawing #s 6.2 & 10

470576.084, 4476590.895

Construct a Rock Bulkhead closure with a bat ladder.

Utilize a minimum three foot (3 ft) length of thirty six inch (36in), 12-guage CSP.

No access door or drain pipe is required.

Table 2 – REVISED Aug. 12, 2026 Item 5.0 – Install Mine Closures - Not Guaranteed

Feature ID Type Description of Mine

Opening Closure Method

General Bid Specifications and

Drawings

UTM

(X,Y) NAD83 Work Description / Notes

CCC136 Adit

Present: 5ft by 6ft Depth: 15 ft Lining: Rock Drainage: No

Rock Bulkhead with Bat Grate

Alternative

Section 14–Rock Bulkhead Closure Section 13-Bat Grate Alternative Std. Drawing #s 6.2 & 10

452209.38, 4402900.61

Construct a Rock Bulkhead closure with a bat ladder.

Utilize a minimum three foot (3 ft) length of thirty six inch (36in), 12-guage CSP.

No access door or drain pipe is required.

CCC137 Adit

Present: 4ft by 5ft Depth: 15 ft Lining: Rock Drainage: No

Rock Bulkhead with Bat Grate

Alternative

Section 14–Rock Bulkhead Closure Section 13-Bat Grate Alternative Std. Drawing #s 6.2 & 10

452626.959, 4400594.240

Remove all trash in and immediately surrounding the mine opening and properly dispose of the material offsite. Construct a Rock Bulkhead closure with a bat ladder. Utilize a minimum three foot (3 ft) length of thirty six inch (36in), 12-guage CSP.

No access door or drain pipe is required.

CCC142 Adit

Present: 2ft by 3ft Depth: >25 ft Lining: Rock Drainage: No

Grated Corrugated Steel Pipe with Bat Grate

Alternative

Section 10–Corrugated Steel Pipe Adit Closure Section 13–Bat Grate Alternative Std. Drawing #s 5 & 6.2

448972.968, 4398024.784

After clearing all loose debris, install a twenty four

(24) inch diameter ten (10) foot length of twelve (12) gauge corrugated steel pipe (CSP) with bat ladder in accordance with Corrugated Steel Pipe Adit Specifications and Bat Grate Alternative. Access door is not required. Drainpipe is not required. Rock grouting around the CSP is required. The CONTRACTOR shall cover the CSP with onsite soil bedding prior to backfill and to reduce the likelihood of damage to the CSP by falling rock from the brow.

In addition, the exterior of the CSP shall be backfilled using onsite material.

Table 3 – REVISED Aug. 12, 2026

Item 6.0 – Maintenance Features - Not Guaranteed

Feature ID Type Description of Mine

Opening Closure Method

General Bid Specifications and

Drawings

UTM

(X,Y) NAD83 Work Description / Notes

143-061 Adit

Present: N/A Depth: 200 ft

Lining:

Drainage: No

Adit Door Repair

Section 12–Adit Door Closure

454788.866, 4397068.986

Replace the vandalized two by two (2 x 2) foot adit door with a new bat accessible adit door.

161-D-32 Crown Hole

Present: 1ft by 2ft Depth: 6ft

Lining: Soil Drainage: No

Machine Backfill

Section 2.0–Backfill Closure

456825. 919, 44 5897.625

Machine backfill in accordance with Backfill Closure Specifications with onsite materials. Five (5) cubic yards of rock fill are required. Six (6) four foot by eight foot (4ft x 8ft) sheets of plywood will be required to protect the resident’s lawn. Storm water sediment control measures shall be implemented prior to work on the closure. Twenty five (25) feet of excelsior waddles shall be installed on the downgradient side of the working area.

224-104 Shaft

Present: 6ft by 8ft Depth: 5ft

Lining: Soil Drainage: No

Machine Backfill

Section 2.0–Backfill Closure

447030.51, 4398218.21

Machine backfill in accordance with Backfill Closure Specifications with onsite materials. Five (5) cubic yards of rock fill are required. Storm water sediment control measures shall be implemented prior to work on the closure. Twenty five (25) feet of excelsior waddles shall be installed on the downgradient side of the working area.

224-119 Adit

Present: N/A Depth: N/A

Lining: Rock Drainage: ~1.5 gmp

Adit Door Repair

Section 12–Adit Door Closure

450333.0926, 4396572.374

Remove and properly dispose of trash within and around the portal. Replace the lock hasp and protective plate so that the adit door may be securely locked.

Table 3 – REVISED Aug. 12, 2026 Item 6.0 – Maintenance Features - Not Guaranteed

Feature ID Type Description of Mine

Opening Closure Method

General Bid Specifications and

Drawings

UTM

(X,Y) NAD83 Work Description / Notes

247-P-75 Shaft

Present: 6ft by 13ft Depth: >100 ft

Lining:

Drainage: No

Panel Door Repair

Section 4–Precast Concrete Panel Closure

455406.395, 4407660.644

Remove and replace the vandalized two by two (2 x

2) foot adit door with a new bat accessible adit door.

Door frame is in good condition.

258-114 Shaft

Present: 10ft by 17ft Depth: UNK Lining: Rock Drainage: No

Machine Backfill

Section 2.0–Backfill Closure

449136.4969, 4403444.708

Machine backfill in accordance with Backfill Closure Specifications with onsite materials. Ten (10) cubic yards of rock fill are required. Storm water sediment control measures shall be implemented prior to work on the closure. Twenty five (25) feet of excelsior waddles shall be installed on the downgradient side of the working area.