Dozer Engulfment Case Study

1
Dozer Engulfment Case Study

• Jack Katlic
• Sr VP-Fuel Supply, AEP- Retired
• Mark Skiles
• Director of Technical Support, MSHA
• Phil Southern
• Bodygard
• Sunnie Southern
• Bodygard

2
Dozer Engulfment Case Study

• Agenda
• Surge Pile Hazards
• Surge Pile Accidents
• Solutions for Stronger Cab Windows
• Demonstration
• Conclusion
• Panel Discussion

3
Dozer Engulfment Case Study

• Purpose
• Share one method the coal industry has
  implemented to save lives

4
Surge Pile Hazards
5
Surge Pile Safety
Slides with the MSHA logo were adapted from the
MSHA website and can be found at www.msha.gov
Directorate of Technical Support
Mine Safety and Health Administration
6
Surge Pile Hazards

• Feeding material acts like quicksand

7
Surge Pile Hazards

• The edge of the drawhole is unstable

8
Surge Pile Hazards

• Poor visibility

9
Surge Pile Hazards

• Since 1980, 19 persons have died in coal mining
  related surge pile accidents
• Most of the accidents have involved a hidden
  cavity created when material bridged over a
  feeder

10
Causes of Bridging Over a Surge Pile Feeder

• Bridging can occur
• When equipment transverses the material at the
  surface of the pile
• Surface material compacts creating a false
  roadway
• Settling in may occur in an idle pile and
  increase risk

11
Surge Pile Accidents
12
Dozer Buried in Cavity
Note the thickness of the material that had been
bridged over
13
Partially Buried Bulldozer in Fatal Accident in
Pennsylvania
A hidden cavity collapsed under the dozer while
it was pushing coal on the pile
14

• Most fatal accidents occurred when the dozer cab
  windows either broke, or were pushed into the
  cab, allowing coal to fill the cab

15
Cab Filled with Coal
The coal has broken or pushed in the cab windows
and filled the cab
16
Windshield pushed back into cab
Note orange object under windshield is an self
contained self rescuer (SCSR)
17
Best Practices Ways to Improve Surge Pile
Safety
18
Best Practices Surge Pile Safety

• Provide equipment cabs strong enough to resist
  burial pressures

19
Solutions for Stronger Cab Windows
20
Available Solutions for Stronger Cab Windows

• MSHA initiative
• Use of very high-strength glass
• Massey approach
• Add supports to the inside of the cab windows -
  combined with using somewhat stronger glass
• Use of polycarbonate windows
• Adequate strength
• Support around edges needs to allow for higher
  deflection
• Issue of scratch-resistance
• Bodygard system
• A customized polycarbonate system

21
Massey Subkit
22
Massey Subkit

• The first system
• Most widely used
• Effective in saving lives
• System design
• is comprised of metal bars attached to the inside
  of the cab
• keep the cab and glass from collapsing on the
  operator

23
The Massey Approach

• Installed support bars on the inside of the cab
  windows
• The supports for the right-side door window are
  shown here

24
The Massey Approach

• Horizontal support bars and additional edge
  support for the windshield are shown here

25
The Massey Approach

• Masseys successful burial demonstration
• The glass cracked but it held the coal out of the
  cab

26
Contrast this scene after the Massey
demonstration - where coal was held out of the
cab - with...
27
This scene from an accident, where coal has
filled the cab...

28
Massey Subkit

• Advantages
• Keeps cabs from collapsing
• Least expensive
• Saves lives

• Disadvantages
• Obscures vision especially when backing up
• Causes cycildelic affects that result in
  complaints of headache from operators
• Metal bars rattle and increase noise level in the
  cabin
• Metal bars loosen and crack door glass that must
  be replaced

29
PPG Preformed Pre-designed Product
30
PPG Preformed Pre-designed Product

• Created as by request of MSHA to overcome the
  deficiencies of the subkit
• System design
• A chemically hardened preformed pre-designed
  product
• Installed by gluing the glass into a gasket is
  installed in same manor as standard glass packages

31
High-strength glass installed using urethane
adhesive
32
Field Burial Demonstration

• Federal No. 2 Mine
• Near Morgantown, WV

33
High-strength glass installed in all cab windows
of test dozer
34
Dozer with high-strength glass being buried in
coal pile
35
Buried dozer being dug out
36
Checking windows after burial
37
High-strength glass intact after burial
demonstration
38
PPG
PPG Preformed Pre-designed Product

• Advantages
• Does not obstruct vision
• Resists static pressure up to 40 psi

• Disadvantages
• Preformed therefore application is limited to
  Caterpillar and Komatsu dozers standard cab
  packages
• Requires fixing of any deformation of the cab
  prior installation of the glass
• Most expensive
• May crack when impacted
• May pop-out under stress

Pounds per square inch
Molds are only for dozers not for end loaders
39
Bodygard System
40
Bodygard System

• Custom engineered
• Custom installed
• Polycarbonate system
• Outboard seat is created
• Material is mechanically attach to the cab
• Inhibits internal collapse
• Unbreakable
• Noise insulator
• On site installation
• All manufacturers
• MSHA approved

41
Case Study History

• Massey conducted drop tests of 3 systems to
  determine the most effective system
• The following demonstration shows the results of
  the test

42
Dozer Drop Test Demonstration
43
Body Guard
Bodygard System

• Advantages
• Unbreakable
• Does not obstruct vision
• Can be made to fit anything (all makes and models
  of existing equipment)
• Absorbs and insulates sound
• Broad based system
• Onsite customized installation on all cabs
• Installed on site by drilling and attaching to
  cab
• Cut to specs and attached to ensure stability

• Disadvantage
• Is less scratch resistant that regular glass
  therefore a protective covering is applied that
  is easy and inexpensive to replace

Protective replicable material is applied to
improve the scratch resistance
44
Conclusion

• Based on the results of the drop test, Massey
  signed a national contract with Bodygard to
  perform their installations

45
BODYGARD
The Safety Window People
1 Lincoln Center, Shinnston, WV 26431
www.bodygard.com 304-592-1980