utility pole collapse type of incident: fatal date of ... · on september 9, 2011, the day before...

1 Alberta Human Services, Occupational Health and Safety

UTILITY POLE COLLAPSE

Type of Incident: Fatal

Date of Incident: September 10, 2011

File: F 6183257

Alberta Human Services, Occupational Health and Safety

TABLE OF CONTENTS

SECTION TITLE PAGE NUMBER

1.0 DATE AND TIME OF INCIDENT 3

2.0 NAME & ADDRESS OF PRINCIPAL PARTIES 3

2.1 Owner 3

2.2 Prime Contractor 3

2.3 Employer(s) 3

2.4 Contractor(s) 3

2.5 Supplier(s) 3

2.6 Workers(s) 3

2.7 Others

3.0 DESCRIPTION OF PRINCIPAL PARTIES 4

3.1 Employers 4

3.2 Worker 4

4.0 LOCATION OF INCIDENT 4

5.0 EQUIPMENT, MATERIAL AND OBSERVATIONS 4

5.1 Equipment and Material 4

5.2 Observations 5

6.0 NARRATIVE DESCRIPTION OF INCIDENT 5

7.0 ANALYSIS 7

7.1 Direct Cause 7

7.2 Contributing Factors 7

8.0 FOLLOW-UP/ ACTION TAKEN 7

8.1 Human Services, Occupational Health and Safety 7

8.2 Industry 8

8.3 Additional Measures 8

9.0 SIGNATURES 10

10.0 ATTACHMENTS 10

File: F 6183257


SECTION 1.0 DATE AND TIME OF INCIDENT

1.1 September 10, 2011 at approximately 3:35 p.m.

SECTION 2.0 NAME AND ADDRESS OF PRINCIPAL PARTIES

2.1 Owner(s)

2.1.1 Altalink, L.P.

2611 – 3rd

Avenue SE

Calgary, Alberta, T2A 7W7

2.2 Prime Contractor

2.2.1 Altalink, L.P.

2611 – 3rd

Avenue SE

Calgary, Alberta, T2A 7W7

2.3 Employer(s)

2.3.1 Galbraith Power (BC) Inc.

1115 -1608 Broadway Street

Port Coquitlam, BC V3C 2M8

2.3.2. Empirica Energy Inc.

3116 Suite C, 16th

Avenue North

Lethbridge, AB T1H 5J6

2.4 Contractor(s)

2.4.1 Greely Rock Ltd.

Box 2072

Revelstoke, BC V0E 2S0

2.5 Supplier(s)

2.5.1 Poletec Industries Ltee./Ltd.

10440 Rue Henault

Montreal Nord, Quebec H1G 5R4

2.6 Worker(s)

2.6.1 Evan Horkoff, Galbraith Power (BC) Inc., Apprentice Lineman

177 Silverado Range Cove SW

Calgary, AB, T2X 0E1

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2.7 Others

2.7.1 RCMP Crowsnest Pass Detachment

SECTION 3.0 DESCRIPTION OF PRINCIPAL PARTIES

3.1 Altalink L.P., an Alberta based large power Transmission Company with more than

600 workers, owns, operates and maintains power lines and was the prime contractor

at the site. Altalink L.P. contracted Empirica Energy Inc. to refurbish part of the 170

L power line including Structure 29.

3.2 Galbraith Power (BC) Inc. was the employer of the deceased worker. On September

9, 2011, the day before the incident, Empirica Energy Inc. and Galbraith Power (BC)

Inc. were amalgamated under the name Galbraith Power (BC) Inc. The amalgamated

Corporation was registered with the British Columbia Registry Services on October 1,

2011. On December 16, 2011, Galbraith Power (BC) Inc. changed its name to

Rokstad Power Corporation in Alberta.

3.3 Prior to restructuring, Empirica Energy Inc. hired a small company, Greely Rock Ltd.

to provide safe access to the sites (scaling) and to drill holes into the rocks to facilitate

the installation of anchors. Greely Rock Ltd., worked under the civil division of

Empirica Energy Inc.

3.4 Poletec Industries Ltee./Ltd., was the supplier of the Tri-Anchor pole mount system

designed to secure utility poles in rocky terrain.

3.5 The fatally injured worker (Evan Horkoff) was a first year lineman apprentice. He

started his apprenticeship on August 2, 2011.

SECTION 4.0 LOCATION OF INCIDENT

The incident occurred at a location approximately 1 km east of Blairmore, Alberta, at

Structure 29 of power line 170 L. Structure 29 was located in rocky, mountainous

terrain above Highway 3 (Refer to Attachment A-Map and Attachment B-

Photographs 1, 2, 3 and 4).

SECTION 5.0 EQUIPMENT, MATERIAL AND OBSERVATIONS

5.1 Equipment and Material

5.1.1 Two wooden poles were part of a temporary structure built to facilitate the removal of

conductors and cross braces from the existing power line poles that were scheduled

for replacement. The conductors had been de-energized.

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5.1.2 The temporary wooden pole involved in the incident was approximately 17 meters

high and weighed 880 kilograms. There was a 3.1 meter long sling attached to the

pole near the top end. A No.9 Tri-Anchor pole mount system was used to secure the

temporary wooden poles to the ground. Galbraith Power (BC) Inc. installed two guy

wires on each of the two temporary poles and a bridal guy wire between the two poles

to provide structural stability.

5.1.3 The No.9 Tri-Anchor pole mount system was designed to be used in solid rock. The

system consisted of modules with hollow metal tubes (sleeves) that, when bolted

together form a tight collar encircling the butt of the pole. According to the

manufacturer’s specifications, rock anchors extend through the sleeves and into .61

meter deep holes pre-drilled into rock. The anchors have expansion shells on the

bottom ends which are inserted into holes drilled into the rock. When the nuts on the

top of the anchors are tightened, the expansion shells expand, to secure the anchors.

The number of modules required depends on the diameter of the pole butt (Refer to

Attachment C- Tri-Anchor manufacturer’s specifications).

5.1.4 The pole mount system at the location did not have Tri-Anchor anchors. Instead, it

was secured to the rock by No.8 DYWIDAG thread bars inserted into 6 foot deep

holes drilled into the rock. The collar was made up of 4 modules. Four DYWIDAG

thread bars were inserted through the hollow metal tubes and into the holes. There

were no expansion shells at the bottom of the DYWIDAG thread bars. Each

DYWIDAG thread bar had a nut on the top end of the module. In addition two of the

thread bars had a bolt at the bottom end. There was no grouting (cementing) of the

DYWIDAG thread bars in to the ground (Refer to Attachment B- Photographs 5).

5.2 Observations

5.2.1 Environment Canada weather records for Crowsnest area show that the temperature at

the time of the incident was approximately 26 C with a wind speed of 20 km/h. The

location where the pole butt was located had considerable overburden consisting of

soil and rock fragments.

5.2.2 Galbraith Power (BC) Inc. personnel had previous experience in the use of the Tri-

Anchor pole mount system but Altalink L.P. was not familiar with the system.

5.2.3 There were no engineering specifications available for the temporary wooden pole

structures installed with a modified Tri-Anchor pole mount system.

5.2.4 Galbraith Power (BC) Inc. personnel at the site had determined that the terrain at the

site of the structure 29 was not solid enough to use the 0.61 meter long anchors of the

Tri-Anchor pole mount system. Instead, Galbraith Power (BC) Inc. decided to drill

1.83 meter deep holes and to use #8 DYWIDAG thread bars as anchors to the Tri-

File: F 6183257


Anchor collars.

SECTION 6.0 NARRATIVE DESCRIPTION OF THE INCIDENT

6.1 On August 17, 2011, Greely Rock drillers (Josh Veres, Bill Ethier) drilled 4 holes for

each of the two temporary poles to a depth of 1.83 meters at locations marked by

Empirica Energy Inc. personnel at the site of the structure 29. The holes were drilled

using a Tri-Anchor template. They inserted a #8 DYWIDAG thread bar into each

hole and slid Tri-Anchor sleeves over the #8 DYWIDAG thread bar.

6.2 On September 9, 2011, Galbraith Power (BC) Inc. line crew consisting of foreman

(Wayne Hanis), lineman 1 (Ron Stewart), lineman 2 (Shawn Gaudrey), lineman 3

(Darren Harvey), trade trainee (Tyler Ebenal), lineman apprentice (Evan Horkoff) and

the general foreman (Nico Geelhoed) arrived on site and installed the Tri-Anchor

modules over the #8 DYWIDAG thread bar to form the collar of the pole mount. The

temporary wooden pole was flown into the location by helicopter and lowered into

the Tri-Anchor collar. The line crew guided the pole butt into the collar and tightened

the collar. Three temporary ropes attached to the pole were connected to ground

anchors to provide stability to the pole.

6.3 The same procedure was repeated for the second pole. After the helicopter left, the

journeyman lineman 1 (Ron Stewart) climbed the poles and attached two guy wires

from each pole and connected them to ground anchors. A third guy wire, called a

“bridal” was attached to connect the two temporary poles horizontally. The three

temporary ropes attached to the pole were removed.

6.4 On September 10, 2011, the line crew (Wayne Hanis, Ron Stewart, Shawn Gaudrey,

Darren Harvey, Tyler Ebenal and Evan Horkoff) returned to the site and installed

work platforms (Baker boards) on the temporary poles. Working from the Baker

boards, the crew proceeded to remove the existing power line. They successfully

lowered the east and west conductors and removed the cross braces and rigging from

the old structure. The crew installed slings on the old poles and the temporary poles to

facilitate their removal.

6.5 After removing the bridal guy wire, they attempted to lower the centre conductor to

the ground. The conductor came down against the west temporary pole which caused

it to lean westward into the side of the mountain, partially pulling out a DYWIDAG

thread bar from ground on the east side of the pole. The line crew managed to lower

the centre conductor by rigging and pulling the conductor towards the east temporary

pole.

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6.6 The crew cut the leaning west temporary pole above the Tri-Anchor attachment and

dropped it to the ground, then flew it out to the storage yard. The old lower pole was

also removed and flown away to the storage yard. The remaining guy wires on the

east temporary pole were removed.

6.7 It was observed that the 3.1 meter sling attached to the temporary pole was not long

enough to reach ground and allow for hook up to the helicopter for removal. With the

permission of the foreman (Wayne Hanis), the apprentice (Evan Horkoff) climbed the

temporary pole to connect an extension sling. He was wearing the required safety

gear and was attached to the temporary pole. When the apprentice (Evan Horkoff)

was close to the sling already attached to the temporary pole, it started to lean.

6.8 The temporary pole fell to the down side of the mountain, partially pinning the

apprentice (Evan Horkoff), under the pole. The foreman (Wayne Hanis) and Lineman

1 (Ron Stewart) immediately climbed down to the location of the apprentice to assist

him.

6.9 The foreman (Wayne Hanis) called the rescue team, the helicopter and Emergency

Medical Services (EMS). The rescue team extracted the injured worker and helped

move him into the helicopter. The helicopter airlifted the injured apprentice (Evan

Horkoff) to an EMS vehicle that was waiting on nearby Highway 3. EMS transported

the injured apprentice (Evan Horkoff) to the Blairmore hospital where he succumbed

to his injuries the same day.

SECTION 7.0 ANALYSIS

7.1 Direct Cause

7.1.1 The apprentice (Evan Horkoff) fell to the ground when a temporary wooden pole he

had climbed fell.

7.2 Contributing Factors

7.2.1 The Tri-Anchor system was not used in accordance with the manufacturer’s

specifications. The surface rock at the location did not meet the manufacturer’s

requirements.

7.2.2 The modifications to the Tri-Anchor system as used to construct a temporary

structure were not performed in accordance with specifications certified by a

professional engineer. There were no engineering specifications for the erection, use

and dismantling of the temporary pole structure.

7.2.3 The #8 DYWIDAG thread bars used as anchors were not grouted in or anchored to

the rock. There was no procedure in place to ensure that #8 DYWIDAG thread bars

were adequately anchored to the rock to support the temporary poles.

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7.2.4 The line crew was not aware that the #8 DYWIDAG thread bars were not adequately

anchored to the rock. Some bolts on the top end of the modules tightened due to the

presence of bolts at the bottom end.

7.2.5 The guy wires holding the pole had been removed prior to the incident.

7.2.6 The sling attached to the pole was not long enough to reach the ground, requiring the

attachment of an extension sling.

SECTION 8.0 FOLLOW-UP/ ACTION TAKEN

8.1 Human Services, Occupational Health and Safety

8.1.1 On September 10, 2011, Occupational Health and Safety (OHS) received an incident

notification. Occupational Health and Safety Officers responded to the scene

immediately and commenced an incident investigation.

8.1.2 OHS issued an order requiring the prime contractor to conduct an incident

investigation and prepare a report.

8.1.3 OHS issued a Demand for documents related to the incident.

8.1.4 OHS issued a stop work order for work activities requiring workers to climb poles

supported by Tri-Anchor systems until the cause for the incident was determined.

8.1.5 OHS hired a consulting geotechnical engineer to evaluate the anchoring system used

at the location to secure the temporary pole.

8.2 Industry

8.2.1 On September 10, 2011 following the incident, Galbraith Power (BC) Inc. voluntarily

stopped work on the 170L power line prior to the arrival of OHS.

8.2.2 Galbraith Power (BC) Inc. stopped using the Tri-Anchor pole mount system.

8.2.3 The prime contractor conducted an incident investigation and submitted a report to

OHS.

8.2.4 The employer and prime contractor complied with all orders issued by OHS.

File: F 6183257


8.3 Additional Measures

8.3.1 When Tri-Anchors are to be utilized, the prime contractor, Altalink, L.P. required all

contractors to obtain an assessment of conditions by a professional engineer to ensure

sufficient anchoring. In addition, all contractor personnel involved in the installation,

use or removal of temporary poles and the Tri-Anchor System are required to be

trained on the procedures and manufacturer’s specifications for their installation, use

and removal.

SECTION 9.0 SIGNATURES

Original Report Signed October 15, 2014

Lead Investigator Date

Original Report Signed October 15, 2014

Reviewer Date

Original Report Signed November 17, 2014

Director Investigations Date

SECTION 10.0 ATTACHMENTS:

Attachment A - Map

Attachment B - Photographs

Attachment C - Tri-Anchor manufacturer’s specifications


GALBRAITH POWER (BC) INC. File: F-6183257

Attachment A

Map

Map – Arrow shows the location of the incident, approximately 1 km east of Blairmore, Alberta.



Attachment B

Photograph 1 of 5

Photograph 1 – Shows the view of the incident site from Highway 3. Arrow shows the fallen

temporary pole.



Attachment B

Photograph 2 of 5

Photograph 2 – Shows an aerial view of the incident site.



Attachment B

Photograph 3 of 5

Photograph 3 – Shows the site of the incident.

1) Old permanent pole (west)

2) DYWIDAG thread bars on the fallen pole pulled out from the ground

3) Tri-anchor collar

4) Stump of the old permanent pole (east)

5) Butt section of the temporary pole (west)

6) Tri-anchor collar on the temporary pole (west)

1

2

3

4

5

6



Attachment B

Photograph 4 of 5

Photograph 4 – Shows the fallen temporary pole on the side of the mountain.



Attachment B

Photograph 5 of 5

Photograph 5 – Shows the butt section of the temporary fallen pole.

1) Pulled out #8 DYWIDAG thread bars

2) Tri-anchor collar

1

2

Attachment C

Tri-anchor manufacturer’s specifications

utility pole collapse type of incident: fatal date of ... · on september 9, 2011, the day before...

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