Midnite Mine Project Report

August 28 – September 3, 2020

PROJECT: Midnite Mine Remediation REPORT NO: 2020-14

OWNER: Newmont/Dawn Mining OPERATOR: Newmont/Dawn Mining

Summary of Work Activities or Events for this reporting period:

This weekly report provides a summary of Midnite Mine Site (Site) remediation action (RA) construction

activities, quality assurance (CQA), quality control (CQC) and engineering activities for the period August

28 – September 3, 2020. The Site activities discussed in this weekly report include, but are not limited to:

Site Health, Safety, and Security; Community Liaison, Project Meetings, Regulatory Oversight, Site

Visitors; Site Mobilization; RA Activities; Project Documentation; and Site Inspections.

The project SharePoint site includes the Project documentation discussed in this report. Access to the

project SharePoint site is available at the following link: https://amcollab.mwhtools.com/sites/midnitemine

SITE HEALTH, SAFETY, AND SECURITY

MIDNITE MINE HEALTH & SAFETY SUMMARY: Reporting Period August 28 – September 3,

2020

FIRST AID INJURY 0 PROPERTY DAMAGE 0

MEDICALLY TREATED INJURY 0 NEAR MISS INCIDENT 0

RESTRICTED WORK INJURY 0 RADIATION PROTECTION PLAN (RPP) – ISSUES

REPORTED

0

LOST TIME INJURY 0

Comments: No incidents to report. All employees remain healthy.

COMMUNITY LIAISON

Newmont are awaiting approval from the TERO Director of the updated Midnite Mine Infectious Disease

Preparedness and Response Plan for Coronavirus Disease (COVID-19).

The subcontractor to Northwest Linings included in their TERO approved Compliance Plan were on site on

September 1 to identify leak locations in South Pond.

The Newmont Sustainability Management Group continue to develop equations to calculate partial

potential compensation for Tribal members that worked at Midnite Mine in 2019 but were not rehired in

2020 that might be provided by Newmont. Newmont are reaching out to the TERO Director for some

additional information.

No issues or concerns were reported or received by Newmont from the Spokane Tribe of Indians

Community Liaison Officer.

PROJECT MEETINGS, REGULATORY OVERSIGHT, AND SITE

VISITORS

Weekly Progress Meeting:

The Weekly Construction Progress meeting was held at 1000 hours on Wednesday, September 2, 2020 at

the on-site conference room and via conference call. Representatives from the following stakeholders

attended the meeting in person or via telephone:

• EPA

• Spokane Tribe of Indians

Midnite Mine Project Report

August 28 – September 3, 2020

• Jacobs

• Dawn Mining Company (DMC)/Newmont

• WME

• Stantec

• AJAX

Meeting Action Items:

• Lou Miller to provide schedule for next sampling event to EPA. Requested data were provided to

EPA on September 2.

EPA Plan/Document Approvals:

• None.

Regulatory Site Visit(s):

• None.

REMEDIAL WORK ACTIVITIES

Construction: During the week of August 28 – September 3, 2020, the following activities were conducted:

• Hillside Waste Rock Pile (HSWRP) Crushing & Screening

o Continued processing material through the crushing and screening plant producing Drain

Gravel and Overliner Protection Layer materials. Drain Gravel was hauled to stockpile

location southwest of the Water Treatment Plant as shown in the 2020 Crushing and

Stockpiling Work Plan. Overliner Protection Layer material was hauled to stockpile located

between Pit 3 and the Laborer’s Laydown.

o One quality control sample of Drain Gravel was collected from the crushing operation.

Gradation results for the samples are pending from the lab. All available lab gradation

data are available on the project SharePoint site and are within specification.

• South Pond Pump Station

o Knight Construction completed hydrostatic and pneumatic pressure tests of the dual-

containment HDPE pipelines of the South Pond Pump Station. All pressure tests

conformed with the project specifications.

o Knight Construction connected South Pond Pump Station HDPE pipelines to the pipelines

in the vaults.

• Leak Location Services Inc (LLSI) performed an electrical leak location survey of the east cell of

the South Pond. An electrical current was applied to the water in the leak detection system while a

detector was pulled along the bottom of the pond at transects 2.5 feet apart. The electrical signal

was detected at 10 locations in the east cell of the pond, indicating probably leak locations. A

couple of the detection locations were found around the east pump riser and may be the same

leak. Each leak location that was detected was marked on the liner and LLSI has provided a

report that indicates the approximate location of each leak. Transfer of water from the east cell to

the west cell of the South Pond has started.

• Continued removing trees from the Pit 4 Overburden Pile and hauling the removed trees to the

south east side of Pit 4, near Area 5.

• Performed weekly South Pond Embankment inspection and Pit 4 tension crack measurement. No

movement identified at either location.

Stormwater Pollution Prevention Plan (SWPPP)

• Monthly SWPPP inspection performed on August 28.

Midnite Mine Project Report

August 28 – September 3, 2020

• A Site walk was held with Newmont, Envirocon, and Stantec to plan winter stormwater controls for

the Site. The SWPPP map will be updated to reflect the stormwater controls, in accordance with

the requirements of the SWPPP, once the controls are finalized.

Spill Prevention, Control, and Countermeasure Activities (SPCC)

• None.

Equipment Mobilized/Demobilized and Material Delivered

The following equipment was mobilized to the Site during this reporting period.

• None.

The following equipment was demobilized from the Site during this reporting period.

• None.

All project owned non-road diesel equipment on Site is US-EPA Tier 4 compliant. On-site rental equipment

and subsequent deliveries of rental equipment may be less than Tier 4 and will be assessed at the time of

delivery.

Materials:

The following material was delivered to the Site during this reporting period.

• None.

CONSTRUCTION QUALITY ASSURANCE

Dust Control and Monitoring

Six dust monitors operated on site during this time-period at the locations and for the time intervals listed in

Table 1 below. There was no exceedance of the total suspended particulate (TSP) action level of 260

µg/m3.

Bison Engineering was on Site on September 2 for monthly calibration of the dust monitors and quarterly

calibration of the meteorological station.

Table 1 - TSP Dust Monitoring Locations during Reporting Period August 28 – September 3, 2020

Monitor ID Location Description Start Date

Status

Fri

Sat-

Su

n

Mo

n

Tu

e

Wed

Th

urs

ES-1 (stationary) Midnite Mine Top of Pit 4 06/03/20 D D D D D

ES-2 (stationary) Midnite Mine Southeast Boundary 06/04/20 D D D D D

ES-3 (stationary) Midnite Mine West Boundary 06/03/20 D D D D D

ES-4 (roving) Spare

ES-5 (roving) North of the South Pond 06/03/20 D D D D D

ES-6 (roving) South of the 1.1 MGD On-Site Water Tank

06/04/20 D D D D D

ES-7 (roving) Northeast of the HSWRP at Pit 4 06/18/20 D D D D D

ES-8 (stationary) Spare

D=Day Shift (6:00 am to 4:30 pm) E=Environmental conditions (Fog, smoke, pollen, heavy rain, etc.) – No Operation

* Equipment malfunction (Battery/Power Supply or Other)

Project Documentation

Midnite Mine Project Report

August 28 – September 3, 2020

Project Submittals, Engineering Change Notices (ECNs), Requests for Information (RFIs), Non-

Compliance Notifications (NCNs), CQA-CQC Field Acceptance Forms and Other Items received, revised

or noted during this time-period are shown in the table below.

Table 2 – CQA Documentation

CQC-CQA Field Acceptance Forms Acceptance No.

Title CQC-CQA Issue Date

None

Project DCNs DCN No. Title Submittal Date EPA Response Date

None

Project ECNs ECN No. Title Submittal Date EPA Response Date

None

Project NCNs NCN No. Title CQA Issue Date CQC Response Date

None

Project RFIs RFI No. Title CQC Submittal Date CQA/EPA Response

Dates

2020-07 Pump Riser Anchor Cable Connection to HDPE Pipe

8/18/2020 CQA – 8/19/2020 EPA – 9/2/2020

2020-08 Fusion Equipment Operator Training 8/19/2020 CQA – 8/20/2020 EPA – 9/2/2020

2020-09 South Pond Emergency Spillway Excavation into Competent Bedrock

8/17/2020 CQA – 8/19/2020 Comments Received

from Jacobs on 8/25/2020

Stantec to Prepare an ECN Based on

Discussions with the EPA

EPA - TBD

Submittals

Submittal No. Title CQC Submittal Date CQA/EPA Response Dates

15196-01 South Pond Pump Station Propane Line Pressure Test

8/18/2020 CQA – 8/19/2020 EPA – 9/2/2020

Other Items Item Title Comments

None

*Accepted with Comments

Copies of the updated CQA Logs are located on the project SharePoint site under the 2020 CQA Folder.

Site Inspections

Details regarding the four-phase CQA observation/inspection process for each definable work feature are

summarized below and are further detailed in the daily CQC/CQA reports that are available on the project

SharePoint site.

Preparatory Inspections / Meetings

None

Initial Phase Inspections

None

Follow-up Phase and Ongoing Inspections

Midnite Mine Project Report

August 28 – September 3, 2020

Daily observations/inspections were performed by CQA during this time-period pursuant to project

specifications, design drawings and project documentation for applicable activities shown in the

Construction portion of the Remedial Work Activities section of this report, including the following:

• SLV Crushing and Screening Operations

• South Pond Pump Station Construction

• South Pond Piping

• South Pond East Cell Leak

• Dust Monitoring System

• Tree Removal from the Pit 4 Overburden Pile

Completion Inspections

None.

THREE WEEK LOOKAHEAD SCHEDULE A copy of the Three Week Lookahead Schedule is provided as Attachment A.

Report completed and submitted by:

David Lee

Project Construction Director

Attachments

• Attachment A – Midnite Mine 3 Week Lookahead Schedule

Photos of pertinent items are provided below.

Midnite Mine Project Report

August 28 – September 3, 2020

Figure 1: Caterpillar 349 excavator clearing trees from the south end of the Pit 4 Overburden Pile.

Figure 2: Thane Fenley (left) of LLSI and Randy Walund (right) of Newmont pull the leak detector across the east cell of South

pond.

Midnite Mine Project Report

August 28 – September 3, 2020

Figure 3: Bison Engineering conducting the quarterly meteorological station calibration

Midnite Mine Project Report

August 28 – September 3, 2020

ATTACHMENT A

MIDNITE MINE THREE WEEK LOOKAHEAD SCHEDULE

Midnite Mine Project Report,

August 28 – September 3, 2020