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Mark Blohm Blohm Consulting LLC. [email protected] 1 QA for DGM Surveys on Adak Island, AK.
Transcript

Mark Blohm

Blohm Consulting LLC.

[email protected]

1QA for DGM Surveys on Adak Island, AK.

•Introduction

•QA Procedures and Results

•Conclusions

QA for DGM Surveys on Adak Island, AK. 2

Introduction

Overall Objectives of Work (OU B-1) Remedial Action (RA) to Identify and Dispose of Munitions and

Explosives of Concern (MEC).

Clear all Munitions to a depth of 4 feet below the top of the mineral layer.

Digital Geophysical Mapping (DGM) is primary method to detect buried MEC.

QA for DGM Surveys on Adak Island, AK. 3

IntroductionOverview What is Quality Assurance (QA) in DGM surveys?-In our case, the

basic QA objectives were to assure that the contractor adhered to approved project plans and met project performance criteria while the work was ongoing.

What is Quality Control (QC) in DGM surveys?- In our case, QC is adherence to a defined set of measurement performance criteria.

QA (Battelle function) is not intended to eliminate the need for or interfere with QC (contractor function).

In this project, QC and QA were guided by a comprehensive set of Measurement Performance Criteria (aka Data Quality Objectives or DQO’s) provided in the Munitions and Explosives of Concern-Quality Assurance Project Plan (MEC-QAPP), and other plans.

The specific QA metrics and procedures also were detailed in a Quality Assurance Surveillance Plan (QASP) generated by Battelle.

QA for DGM Surveys on Adak Island, AK. 4

Introduction

Project Team Organization:

QA for DGM Surveys on Adak Island, AK. 5

Introduction Location:

QA for DGM Surveys on Adak Island, AK. 6

Introduction Location:

QA for DGM Surveys on Adak Island, AK. 7

Introduction Location:

QA for DGM Surveys on Adak Island, AK. 8

MM-10-F

Introduction

QA for DGM Surveys on Adak Island, AK. 9

•411 Grids

•~352 Acres

•11 Contractor DGM

Crews

Introduction

QA for DGM Surveys on Adak Island, AK. 10

DGM coverage at MM-10-F

•Approximately 1,176

linear miles of DGM.

•36,738 DGM targets

(approximately 104/acre)

•Field DGM and all QA of

Field DGM is 100%

complete.

•Intrusive operations

approximately 25%

complete.

Introduction (Location)

QA for DGM Surveys on Adak Island, AK. 11

Introduction (Location)

QA for DGM Surveys on Adak Island, AK. 12

Introduction (Location)

QA for DGM Surveys on Adak Island, AK. 13

Introduction Review of Digital Geophysical Mapping (DGM)

Methodology: Man-portable EM61-MK2 systems were utilized due to rough terrain.

QA for DGM Surveys on Adak Island, AK. 14

Introduction Review of Digital Geophysical Mapping (DGM)

Example DGM data from single profile over target.

Profile Location

EM61-MK2 Response

*Response is typically a single,

symmetric positive peak (anomaly),

centered over target location.

*The goal of QC (contractor) and QA

(Battelle) is to assure repeatability of

and accuracy of this anomaly.

QA for DGM Surveys on Adak Island, AK. 15

Introduction Review of Digital Geophysical Mapping (DGM)

Example DGM data coverage over a survey grid.

QA for DGM Surveys on Adak Island, AK. 16

Introduction Review of Digital Geophysical Mapping (DGM)DGM Targets from Grid Data.

QA for DGM Surveys on Adak Island, AK. 17

Targets to

Target list

and

Intrusive

Teams

QA Procedures and Results

QA of DGM data was performed after Contractor QC approved the DGM and was comprised of the following primary steps:

Complete review of contractor equipment tests.

Complete re-processing (from raw data to final target maps) of the contractor DGM data.

Comparison of Contractor and QA target lists to provide a final target list (Target Concurrence).

Additional QA procedures included:

Field QA Surveillances

QA Blind Seed Program

Post Intrusive QA Confirmation DGM Mapping

QA for DGM Surveys on Adak Island, AK. 18

Simplified DGM Data

Process

QA Procedures and ResultsContractor QC tests/procedures and performance criteria pertaining to DGM:

QA for DGM Surveys on Adak Island, AK. 19

Data TypeQC Sample and/or Activity to Assess Measurement

PerformanceMeasurement Performance Criteria

Raw Geophysical Sensor

Data

Standardization tests: QC audit of response test recordsResponse above background to standard object will not vary more than 20% for the instrument

used (Geonics EM61-MKII or approved equivalent)

All DGM grid data will be checked by the data

processors to ensure adequate coverage is obtained.

Total positioning holidays or “drop-outs” will not exceed 2% of the accessible area surveyed. If

the total area of the gaps exceeds this percentage, data will be recollected in those gaps if possible.

Operator ensures settings in data logger are set to project

requirements prior to geophysical data collection.Minimum data density of twelve points per second (approximately one point per 0.15 meter)

Noise Error: Referenced amplitude to be determined

during GPO; Standard deviation of background noise in

daily instrument checks to be calculated and assessed

during field activities

Maximum standard deviation of noise not to exceed 20% of the amplitude for the signal for a

horizontal 60mm mortar at 1.5 feet bgs

Raw Positional Data

QC audit of positioning system error test records (Sensor

Positioning Test)

Grid corners will be selected during the data processing of the grid data. Offsets can be measured

from the pick locations. Determined location must be within 2.5 ft of known location.

QC audit of actual grid digital geophysics maps.

Total positioning holidays or “drop-outs” will not exceed 2% of the accessible area surveyed. If

the total area of the gaps exceeds this percentage, data will be recollected in those gaps if

possible.

Processing and

Interpretation

Accuracy of interpreted anomaly locations assessed

during reacquisition of interpreted target anomaly

location

Interpreted location of anomalies within 2.5 ft radius of actual location.

OC review of identification of blind seed item location100 percent of all blind seed items installed by the UXOQCS will be accurately located to within

2.5 foot radius.

Last lane of grid is recollected from opposite direction

and compared (repeat line test and sensor position test)

Accuracy-Positional difference is <1.25ft.

Precision-Relative percent difference (RPD) in anomaly signal strength is less than +/- 20%.

QC audit of “latency” test recordsTotal positional error of merged data set will not exceed 0.5m based on a collection speed of 1.34

m/s (3mph). Collection speed must be less than 1.34 m/s (3 mph).

Comparison of primary target anomaly picks to QC picks

and comparison of combined primary and QC picks to

QA target anomaly picks.

RPD between primary and QC list is less than +/- 20%. RPD between primary /QC picks and QA

picks is less than +/-10%.

QA Procedures and Results

QA for DGM Surveys on Adak Island, AK. 20

Static-Standard Set-up

Static-Standard Data

Measurement Performance

Criteria: Raw Geophysical

Sensor Data-Standardization

Test

QA Procedures and Results

QA for DGM Surveys on Adak Island, AK. 21

Repeat Line Test

Measurement Performance Criteria:

Processing and Interpretation-

Repeat Line Test

QA Procedures and Results

QA for DGM Surveys on Adak Island, AK. 22

Contractor DGM QC Summary Documentation

QA Procedures and Results

QA for DGM Surveys on Adak Island, AK. 23

QA DGM Summary Documentation

QA Procedures and Results

QA for DGM Surveys on Adak Island, AK. 24

QA DGM Summary

Documentation(Detail of portion of Contractor

Section)

QA Procedures and Results

QA for DGM Surveys on Adak Island, AK. 25

QA DGM Summary Documentation(Detail of QA portion)

QA Procedures and Results

QA for DGM Surveys on Adak Island, AK. 26

QA Flags and Minor Incidents were handled via weekly QC teleconferences,

and email communications between QA/Navy and Contractor.

This allowed rapid resolution of minor (but potentially problematic) issues.

Minor QA Issues

Intermittent Failures of Equipment Tests

Incomplete Deliverable Packages

Differences in Target Selection methods between Contractor and QA

Documentation of Inaccessible Areas

QA Procedures and Results

QA for DGM Surveys on Adak Island, AK. 27

Major QA Incidents were handled by:

1) Initial discussion via weekly QC teleconferences, and email communications

between QA/Navy and Contractor.

2) If Issue was not resolved, a Non-Conformance Report (NCR) was issued.

Major QA Incidents

Method of Mounting GPS antenna on EM61-Resolved via email and other communications

Repeated Failure of Equipment Tests and subsequent rejection of Field Data-Resolved via NCR

Missed QA seed-Resolved via NCR

QA Procedures and Results

QA for DGM Surveys on Adak Island, AK. 28

QA Reporting/Documentation

QA Procedures and Results

QA for DGM Surveys on Adak Island, AK. 29

Target Distribution at MM10F

QA Procedures and Results

QA for DGM Surveys on Adak Island, AK. 30

Target Distribution at MM10F-Total Targets per Grid

Conclusions

QA of Contractor DGM Surveys Results:

Resolution of numerous “minor” deviations from project Measurement Performance Criteria in near real time.

Rapid resolution of several “major” deviations via Non Conformance Reports.

Independent evaluation of 100% of Contractor DGM Data and Target selection provides a very high confidence of results of DGM surveys. 36,738 targets identified in MM 10-F.

More than 500 DGM certification packages generated (due to changes in target picking threshold).

QA evaluation of DGM data (Target distribution) provides a “roadmap” for future field QA activities.

QA for DGM Surveys on Adak Island, AK. 31


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