1. Scaling and Bolting or Shotcrete

2. 56 & Definitions.
The following definitions apply in this subpart.
Rock burst. A sudden and violent failure of overstressed rock resulting in the instantaneous release of large amounts of accumulated energy. Rock burst does not include a burst resulting from pressurized mine gases.

3. 56 & Definitions.
Rock fixture. Any tensioned or nontensioned device or material inserted into the ground to strengthen or support the ground.
Travelway. A passage, walk, or haulageway regularly used or designated for persons to go from one place to another.

4. 56 & 57.3200 Correction of Hazardous Conditions
Ground conditions that create a hazard to persons shall be taken down or supported before other work or travel is permitted in the affected area. Until corrective work is completed, the area shall be posted with a warning against entry and, when left unattended, a barrier shall be installed to impede unauthorized entry.

5. 56\ PPM
This standard prohibits work or travel, other than corrective work, in areas where hazardous ground conditions exist. Posting of a warning against entry is required until corrective work is completed if workers could enter the area inadvertently.

6. 56\ PPM Cont.
In addition, barriers are required if the area is left unattended prior to the completion of the corrective work. The mode of travel in the area must be evaluated to determine what type of barrier is appropriate to "impede" unauthorized entry.

7. 56\ PPT Cont.
Examples of barriers would be piles of muck, piles of large boulders or a timber barricade. These barriers would have openings to allow access for persons who are correcting the hazardous conditions. These posting and barrier requirements do not apply to underground face areas under development where the corrective work is performed on a continuing basis as a part of the mining cycle, and the only workers exposed are those engaged in the corrective activity.

8. 56 & 57.3201 Location for Performing Scaling.
Scaling shall be performed from a location which will not expose persons to injury from falling material, or other protection from falling material shall be provided.

9. 56 & Scaling Tools.
Where manual scaling is performed, a scaling bar shall be provided. This bar shall be of a length and design that will allow the removal of loose material without exposing the person performing the work to injury.

10. Hand verses Mechanical Scaling
Scaling Bar
Mechanical Scaler

11. Hand Scaling
Allows for a detailed assessment of rockmass integrity by close observation and “feeling the rock”
Allows the back to be sounded by hand.
Effectiveness dependent upon the skill and experience of personnel
Economical

12. Mechanical Scaling
Allows operators to maintain a safer distance from area being scaled.
Can reach higher into back or fall cavities.
Applies greater force to loose blocks

13. Data from underground mines in Sweden

14. ROOF BOLTING
Scaling
Shotcrete

15. Rock Bolt Installation
More versatile
Costly
Limited
Inexpensive

16. 56 & Rock Fixtures.
(a) When rock bolts and accessories addressed in ASTM F432-95, "Standard Specification for Roof and Rock Bolts and Accessories", are used for ground support, the mine operator shall--

17. 56 & Rock Fixtures.
(1) Obtain a manufacturer's certification that the material was manufactured and tested in accordance with the specifications of ASTM ; and,
Where does MSHA test these bolts?

18. 56 & Rock Fixtures.
(2) Make this certification available to an authorized representative of the Secretary.

19. 56 & Rock Fixtures.
(b) Fixtures and accessories not addressed in ASTM F may be used for ground support provided they-
(1) Have been successful in supporting the ground in an area with similar strata, opening dimensions and ground stresses in any mine; or

20. 56 & Rock Fixtures.
(2) Have been tested and shown to be effective in supporting ground in an area of the affected mine which has similar strata, opening dimensions, and ground stresses as the area where the fixtures are expected to be used. During the test process, access to the test area shall be limited to persons necessary to conduct the test.

21. 56 & Rock Fixtures.
(c) Bearing plates shall be used with fixtures when necessary for effective ground support.

22. 56 & Rock Fixtures.
(d) The diameter of finishing bits shall be within a tolerance of plus or minus inch of the manufacturer's recommended hole diameter for the anchor used. When separate finishing bits are used, they shall be distinguishable from other bits.

23. Roof Bolting Roof Bolting
Support Principles
Support Parameters
Shotcrete
Today I’ll Be covering these 4 topics

24. What is the Bolt System Designed to do?
Bolting Principles
What is the Bolt System Designed to do?
Beam building
Suspension
Keying
Surface control - natural arch

25. Individual laminations bound together to form a single beam
Beam Building
Support Principles
Weak
Strata
Laminated
Beam Building:
No competent strata exists.
Bolt weaker laminated strata to build a strong beam.
Individual laminations bound together to form a single beam

26. Suspension Competent Strata Weak Strata Anchorage Zone Suspended layer
Support Principles
Competent
Strata
Anchorage Zone
Weak
Strata
Suspended layer
Suspension:
Hang the weaker strata from a more competent overlying strata.

27. Keying Fractured Rock Weak Strata Support Principles Keying:
Bolt pieces of fractured strata in place.

28. Highly jointed, altered or
Surface Control
Support Principles
Highly jointed, altered or
weathered rock

29. Bolting Principles Beam building Suspension Keying
Surface control - natural arch

30. Critical Parameters Bolt Type Strength Grade Diameter Length
Density (spacing)
Plate

31. Types of Bolts Friction Anchored Mechanical Fully Grouted
Tensioned Rebar
Combination/Point Anchored
Mechanically Anchored/Resin Assisted

32. Support Characteristics
* Anchorage
* Clamping
* Vertical Stiffness
* Horizontal Stiffness
All roof bolts have certain support characteristics

33. Splitsets or Swellex Bolts
Friction Anchored Support
Splitsets or Swellex Bolts
Split sets provide minimal support (~1 ton per foot of anchorage) when utilized in a suspension application.

34. FRICTION ANCHORED BOLTS
SPLIT TUBE
EXPANDING TUBE

37. MECHANISMS OF FRICTION ANCHOR BOLTS
LOW ANCHORAGE
DEVELOPED ALONG
BOLT LENGTH
LITTLE OR NO SHEAR
RESISTANCE ALONG
SLIPS AND JOINTS
UNLESS INTERSECTED
BY BOLT
NO CLAMP
LOADS
LOW PLATE LOADS

38. Split Sets Inexpensive Easy to Install No resin cartridges
Can be installed in soft or shifting ground

39. SPLITSET

40. RADIAL FORCE

41. SWELLEX
PSI

42. DYWIDAG BOLT

43. Friction Anchor Bolts

45. Critical Parameters Bolt Type Plate Strength Length Density (spacing)
Grade
Diameter
Length
Density (spacing)
Plate

46. EXPANSION SHELL ANCHOR BOLT

47. PARTS OF A BOLT SHELL PLUG SUPPORT NUT (PAL NUT or JAM NUT)
STANDARD ( HARD ROOF )
BAIL ( SOFT ROOF )
PLUG
SPREADS SHELL
SUPPORT NUT (PAL NUT or JAM NUT)
HOLDS SHELL IN PLACE - THEN BREAKS AWAY

48. PARTS OF A BOLT cont. WASHER
ACTS AS LUBRICATION BETWEEN PLATE AND BOLT HEAD

49. WHAT DOES GRADE OF A BOLT MEAN ?
GRADE 75 MEANS THE BOLT HAS A TENSILE STRENGTH 75,000 PSI
TENSION BOLTS
GRADE 60 MEANS THE BOLT HAS A TENSILE STRENGTH 60,000 PSI
NONTENSION BOLTS

50. WHAT DOES THE TERM #5 REBAR MEAN ?
THE DIAMETER OF BOLT ARE STAMPED IN 1/8 INCH INCREMENTS
SO A #5 HAS A DIAMETER OF 5/8 INCH
A CIRCLE AROUND THE NUMBER MEANS IT IS A DEFORMED BAR
5/8 INCH REBAR = 5

51. ROOF BOLT HEAD MARKING
Grade 55
5/8 INCH
DIAMETER 5

52. ROOF BOLT MARKINGS GRADE DIAMETER DESIGNATION 40 3/4 INCH UP NONE
/8 INCH UP X
/8 INCH UP

53. MECHANICAL BOLTS BAIL STANDARD Plugs Bail Shell Leaves Support Nut

54. STANDARD 4 LEAF TYPE EXPANSION SHELL

55. THREE PRONG EXPANSION SHELL

56. TWO LEAF BAIL TYPE EXPANSION SHELL

57. JAM NUT
TO STRONG

58. JAM NUT
TOO STRONG
( DOES NOT
BREAK AWAY
AND DEFORMS
THE SHELL )

59. DEFORMED SHELL

60. JAM
NUT
TOO
WEAK

61. JAM NUT
TOO WEAK
( BREAKS AWAY TOO SOON AND DOES NOT EXPAND SHELL )

62. 56 & Rock Fixtures.
(f) When rock bolts tensioned by torquing are used as a means of ground support,
(1) Selected tension level shall be-
(i) At least 50 percent of either the yield point of the bolt or anchorage capacity of the rock, whichever is less; and

63. 56 & Rock Fixtures.
(ii) No greater than the yield point of the bolt or anchorage capacity of the rock.
WHAT IS ANCHORAGE CAPACITY OF THE ROCK & HOW DO WE MEASURE IT?

64. WHAT IS THE RELATIONSHIP BETWEEN THE WASHER AND THE TENSION IN THE BOLT ?
THE “K” FACTOR IS THE RELATIONSHIP BETWEEN THE WASHER & TENSION IN BOLT
NO WASHER K = 40
HARDENED WASHER K = 50
ANTIFRICTION WASHER K = 75 > 125
HARD PLASTIC

66. K FACTOR cont. TENSION IN BOLT = K x TORQUE
FOR A BOLT USING A HARDEN WASHER AND HAS A TORQUE OF FT- LBS
TENSION IN BOLT = 50 x 150
TENSION IN BOLT = LBS

67. BOLT STRENGTH

68. MECHANISMS OF MECHANICAL BOLTS
MODERATE TO HIGH ANCHORAGE DEPENDING ON THE STRATA
MODERATE
CLAMP
LOADS
CLAMP LOADS DEVELOP
SOME SHEAR RESISTANCE
ALONG BEDDING PLANES,
SLIPS AND JOINTS
MODERATE PLATE LOADS

69. 56 & Rock Fixtures.
(2) The torque of the first bolt, every tenth bolt, and the last bolt installed in each work area during the shift shall be accurately determined immediately after installation. If the torque of any fixture tested does not fall within the installation torque range, corrective action shall be taken.

70. FULLY GROUTED BOLTS

71. 56 & Rock Fixtures.
(g) When grouted fixtures can be tested by applying torque, the first fixture installed in each work place shall be tested to withstand 150 foot-pounds of torque. Should it rotate in the hole, a second fixture shall be tested in the same manner. If the second fixture also turns, corrective action shall be taken.

72. 56 & Rock Fixtures.
(h) When other tensioned and nontensioned fixtures are used, test methods shall be established and used to verify their effectiveness.
(i) The mine operator shall certify that tests were conducted and make the certification available to an authorized representative of the Secretary.

73. 56\ Rock Fixtures PPM
This standard contains the requirements for installation and testing of all rock fixtures and accessories used for ground support. In all cases where rock fixtures are selected as the method used to support ground, they must meet the requirements of 56/

74. 56\ PPM Cont.
All bolts tensioned by torquing must be within the torque range set out in paragraph (f)(1). Mine operators are required to test the first, tenth and last bolt installed in each work area during the shift as a check on whether or not the torquing requirements are being achieved. When the testing process reveals that a fixture is not properly torqued, steps must be taken to determine the extent of defective installation and to correct all improperly installed fixtures.

75. 56\ PPM Cont.
The ground conditions in many active face areas require the installation of only a few bolts during each blasting cycle. Testing of the first and last bolts in each work area will help ensure the integrity of the ground in these instances. Where large numbers of bolts are installed on a continuing basis, testing of the first, tenth and last bolt in each work area would normally provide the frequency of testing necessary to identify a bolting problem and enable the operator to take corrective action.

76. 56\ PPM Cont.
The mine operator must certify that all tests required by this standard have been conducted. In the case of testing of the ASTM bolts and accessories by the manufacturer of the devices, the mine operator's certification responsibility is satisfied by obtaining a copy of the manufacturer's certification and making it available to the inspector

77. 56\ PPM Cont.
The correction of improperly installed fixtures will also help to ensure compliance with standard which requires that wall, bank and slope stability be maintained at surface mines where miners are exposed, and standard , which requires that ground support systems at underground mines be designed, installed and maintained to control the ground where miners are exposed.

78. MECHANISMS OF FULLY GROUTED BOLTS
NO CLAMP
LOADS
HIGH ANCHORAGE
DEVELOPED ALONG
BOLT LENGTH
HIGH SHEAR RESITANCE
ALONG RESIN/ROCK
INTERFACE
LITTLE OR NO SHEAR
RESISTANCE ALONG
SLIPS AND JOINTS
UNLESS INTERSECTED
BY BOLT
LOW PLATE LOADS

79. RESIN ANCHOR TORQUE TENSION BOLT
IN THE FIRST TYPE OF INSTALLATION, TWO FOOT OF FAST SETTING RESIN IS USED, AND THE REST OF THE HOLE IS LEFT OPEN

80. RESIN ANCHOR TORQUE TENSION BOLT
SECOND TYPE, ONE TO TWO FOOT OF FAST SETTING RESIN IS PUT IN THE BACK OF THE HOLE, WHILE SLOW SETTING RESIN IS PUT IN THE BOTTOM OF THE HOLE

81. TENSIONED REBAR TENSION NUTS Threaded Deformed Bar Aluminum Plug
Cast Dome
Shear Pin
Tension Nut
TENSION NUTS

82. MECHANISMS OF TENSIONED REBAR BOLTS
EXTREMELY HIGH
ANCHORAGE REGARD-
LESS OF STRATA
HIGH SHEAR RESISTANCE
ALONG RESIN/ROCK
INTERFACE
VERY HIGH
CLAMP LOADS
CLAMP LOAD DEVELOPS
VERY HIGH SHEAR
RESISTANCE ALONG
SLIPS AND JOINTS
VERY HIGH PLATE LOADS

83. MECHANICAL BOLTS (RESIN ASSISTED) Compression Tube Deformed Bar

84. RESIN POINT ANCHOR WITH REBAR SUPPLEMENT

85. RESIN POINT ANCHOR WITH STEEL PIPE SUPPLEMENT

86. RESIN POINT ANCHOR WITH SHEAR PIN & COMPRESSION RING

88. MECHANISMS OF POINT RESIN ANCHORED BOLTS
HIGH ANCHORAGE EVEN IN SOFT ROCK
CLAMP LOADS DEVELOP
MODERATE SHEAR
RESISTANCE ALONG BEDDING
PLANES,SLIPS AND JOINTS
HIGH
CLAMP
LOADS
HIGH PLATE LOADS

89. COMBINATION BOLT Threaded Deformed Bar Grout Column Tensioning Coupler
Shear
Pin
Bearing Plate

90. WHAT IS A SHEAR PIN ?

92. MECHANISMS OF COMBINATION BOLTS
EXTREMELY HIGH
ANCHORAGE REGARDLESS
OF STRATA
GROUTED LENGTH
REINFORCES THE STRATA
LIKE A FULLY GROUTED BOLT
VERY HIGH
CLAMP LOADS
CLAMP LOADS DEVELOPS
HIGH SHEAR RESISTANCE
ALONG BEDDING PLANES,
SLIPS AND JOINTS
VERY HIGH PLATE LOADS

93. Support Characteristics
Vertical
Stiffness
Horizontal
Stiffness
Bolt Type
Anchorage
Clamping
Fully
Grouted
Mechanical
Combination
Point
Anchor
Tensioned
Rebar
Very
High
Moderate
Low
Medium/
Low/
Medium
Frictional
Anchors
Low
Low
Low
Low

94. (Split Sets, Swellex, Friction Loc)
Full Contact Supports
Anchorage Length
* Resin Anchored
* Friction Anchored
(Split Sets, Swellex, Friction Loc)
The anchorage attained is dependent on the length of the anchor

95. Friction Anchor Resin Anchor
1 Ton Per Foot
10 Tons+ Per Foot
Both have increasing anchorage with increasing length, but, a resin anchor is 10 times stronger than a friction anchor.

96. Anchorage Variable Anchorage Constant Along Bolt Length
Along The Bolt Length
Illustrates the primary difference between Full Contact and point anchored/tensioned supports.
FULL CONTACT
SUPPORT
POINT ANCHORED
SUPPORT

97. POINT ANCHORED SUPPORT (MECHANICAL BOLT)
Anchorage
1 Ton/Ft.
(10 Tons)
Anchorage
10 Tons
10’
FRICTION ANCHORED
SUPPORT
(SPLIT SET)
POINT ANCHORED
SUPPORT
(MECHANICAL BOLT)

98. POINT ANCHORED SUPPORT
Anchorage
1 Ton/Ft
(8 Tons)
Anchorage
10 Tons 8’
10’
FRICTION ANCHORED
SUPPORT
POINT ANCHORED
SUPPORT

99. Anchorage 1 Ton/Ft (1 Ton) Anchorage 10 Tons FRICTION ANCHORED SUPPORT1’
Anchorage
1 Ton/Ft
(1 Ton)
Anchorage
10 Tons
10’
That’s why Split Sets are not good for supporting loose or jointed rock.
FRICTION ANCHORED
SUPPORT
POINT ANCHORED
SUPPORT

100. Critical Parameters Strength Bolt Type Length Density (spacing)
Grade
Diameter
Length
Density (spacing)
Other hardware (plates, washers, straps)
Bolt strength is dependent on the grade and size.

101. Bolt Strength Rock Bolts Friction Anchored Bolts Cable Bolts
5/8” Grade 55
19,200lbs.
1-1/8” Grade 100
95,400lbs.
Friction Anchored Bolts
Ring Strength - 20, ,000lbs.
Cable Bolts
.6” strand - 60,000lbs ” strand - 70,000lbs.

102. Break Time