GROUND CONTROL

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GROUND CONTROL

• BASIC GEOLOGY, MINING METHODS AND GROUND CONTROL
  HAZARDS
• UNDERGROUND

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BASIC GEOLOGY

• THE STUDY OF THE EARTH IS CALLED GEOLOGY
• THE SOLAR SYSTEM INCLUDING EARTH WAS FORMED WITH
  GREAT FORCE AND HEAT INTERACTING WITH GRAVITY
• THE EARTH COOLED WHICH RESULTED IN BUCKLING AND
  CRACKLING CAUSING PLACES OF ELEVATION AND
  DEPRESSION.

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BASIC GEOLOGY

• STRONG WINDS, WATER VAPOR AND ACIDS WEATHER ROCKS
  AND MINERALS
• WEATHERING OF BEDROCK PRODUCES FINE PARTICLES
  FORMING SOIL OVER ROCK
• FORCES OF EROSION CARRY AWAY SOIL CREATING
  DEPOSITS OF SEDIMENTS
• PRESENT DAY ROCKS AND MINERIALS FORMED

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BASIC DEFINITIONS

• Mineral - a naturally occurring inorganic
  compound with fairly definite physical properties
  and chemical composition.
• Rock - extensive mineral bodies, composed of one
  or more minerals in varying proportions, which
  constitute an important part of the
  earths crust.
• Ore - are minerals from which one or more metals
  may be extracted at a profit.

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TYPES OF ROCKS

• IGNEOUS-SOLIDIFIED FROM MOLTEN MATERIAL AND
  INCLUDE GRANITE, FELSITE, DOLERITE AND BASALT
• SEDIMENTARY-DEPOSITED AS A RESULT OF EROISION AND
  INCLUDE SAND, GRAVEL, SILT CLAY AND LIME
  DEPOSITS
• METAMORPHIC- IGNEOUS SEDIMENTARY ROCK WHICH
  CHANGED FORM BY HEAT PRESSURE AND INCLUDE
  SLATE, ANTHRACITE COAL, SANDSTONE, LIMESTONE,
  QUARTZITE AND MARBLE.

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TYPES OF MINERAL DEPOSITS

• MASSIVE--CONSIDERABLE LATERAL AND VERTICAL EXTENT
  WITH UNIFORMLY DISTRIBUTED ORE SUCH AS DOME SALT
  AND LEAD-ZINC DEPOSITS
• BEDDED OR STRATA-BOUND--PARALLELS STRATIFICATION
  OF MOST OFTEN SEDIMENTALY ROCK, LATERALLY
  EXTENSIVE AND LIMITED THICKNESS SUCH AS COAL,
  POTASH, COPPER AND URANIUM DEPOSITS.

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• NARROW VEIN-- A TYPICALLY LONG, NARROW ZONE OR
  BELT OF ORE OFTEN DIPPING STEEPLY AND USUALLY
  LYING IN BOUNDARIES SEPARATING IT FROM
  NEIGHBORING ROCK SUCH AS NARROR VEINS OF GOLD OR
  METALLIC MINERALS
• WIDE VEIN-- AS DEFINED ABOVE EXCEPT THAT THE VEIN
  THICKNESS IS GREATER THAN 10 FEET.
• LENTICULAR OR POCKET--ISOLATED ORE BODY OR AN
  ENRICHMENT OF LIMITED VERTICAL OR HORIZONTAL
  EXTEND IN A MASSIVE, BEDDED OR VEIN DEPOSIT SUCH
  AS LEAD, ZINC OR IRON

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• PORPHYRY--DISSEMINATED COPPER MINERALS IN A FINE
  GRAINED IGNEOUS ROCK MATRIX SUCH AS LARGE COPPER
  DEPOSITS
• PLACER-FORMED BY SEDIMENTARY PROCESSES AT THE
  SURFACE OR NEAR-SURFACE CONTAINING MINERAL
  PARTICLES SUCH AS GOLD AND PLATINUM IN SAND OR
  GRAVEL

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GEOLOGY AND GROUND CONTROL

• Geology can be variable and geological conditions
  cannot usually be changed.
• Mine planning must take into account as much
  detail as possible about the geological
  conditions that will be encountered by the mining
  operation.
• Ground support method will be dictated by the
  geological conditions that will be encountered in
  the mining operation.

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UNDERGROUND MINING TERMS
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UNDERGROUND MINING METHODS

• ROOM AND PILLAR
• LONGWALL
• CUT AND FILL
• STOPES
• BLOCK CAVING
• SQUARE SET

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CAUSES OF UNDERGROUND GROUND CONTROL PROBLEMS

• BLASTING PRACTICES
• FAILURE TO SCALE LOOSE GROUND
• WATER EFFECTS
• GEOLOGICAL--FAULTS, SEAMS,OR POOR GROUND

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FAILURES AND GEOLOGY

• Underground
• Roof falls
• Span
• Discontinuities
• Rib rolls (falls)

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PREVENTATIVE MEASURES

• Geology
• Qualitative description of conditions
• Rock types both composition extent
• Discontinuities
• Numerical rating of rock - a consistent method to
  evaluate rock and put the results into a format
  that can be used for subsequent comparison and
  engineering design.

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PREVENTATIVE MEASURES CONTINUED

• Mine design
• Strength of rock (compressive, tensile, shear)
• Shape of openings
• Size of openings and pillars
• Number of openings and spatial relation
• Vertical and/or Horizontal stress

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PREVENTATIVE MEASURES CONTINUED

• Recognizing hazards
• Use your eyes and ears to evaluate conditions
• Cracks, joints or loose pieces
• Weight on pillars, roof, and supports
• Be alert when rock composition changes
• Floor heave
• Wet conditions

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PREVENTATIVE MEASURES CONTINUED

• Scaling
• Factors to consider
• Scaling Vs. Bolting
• Two methods of scaling
• Manual (hand) - equipment, location, technique
• Mechanical (remote) - safer, sensitivity

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VISUAL INSPECTIONS-ROOF RIB

• STRESS CRACKS IN ROOF, FLOOR RIB
• KETTLEBOTTOMS, CLAY VEINS, OR ABNORMAL ROCK
  FORMATIONS
• A FORMERLY DRY PLACE THAT BECOMES WET
• SMALL CHIPS OR BARK AROUND TIMBERS
• MOISTURE OR CRACKS THAT APPEAR IN THE ROOF AFTER
  BEING SUPPORTED

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VISUAL INSPECTIONS-SUPPORTS

• BENT CROSSBARS, TIMBERS, OR POSTS OR HEAVY
  PRESSURE
• ROCK BOLT BEARING PLATES THAT SHOW SIGNS OF
  STRESS
• CAP PIECES SQUEEZED DOWN AND OVER POSTS
• TIMBERS DECAYED THROUGH TIME.

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PROPER ROOF TESTING

• VISUAL EXAMINATION
• SOUND AND VIBRATION METHOD
• ALWAYS STAND UNDER SUPPORTED ROOF WHEN TESTING
• ALWAYS START FROM SUPPORTED ROOF AND EXAMINE
  TOWARD THE FACE
• NEVER TURN YOUR BACK TO THE FACE OR RIB WHEN
  TESTING

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PROPER ROOF TESTING

• START TAPPING THE ROOF LIGHTLY AT FIRST WITH A
  SOUNDING ROD THEN INCREASE YOUR STROKE TO HEAR
  THE SOUND OF THE ROOF AND/OR FEEL THE VIBRATION
• ALWAYS USE AN APPROVED TESTING TOOL
• ALWAYS WEAR GOGGLES TO PROTECT YOUR EYES

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Precautions- Surface Only
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57.3430 Activity Between Machinery or Equipment
and the Highwall or Bank.

• Persons shall not work or travel between
  machinery or equipment and the highwall or bank
  where the machinery or equipment may hinder
  escape from falls or slides of the highwall or
  bank. Travel is permitted when necessary for
  persons to dismount.

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57.3430 PPM

• This standard is applicable to surface mines and
  surface areas of underground mines. It addresses
  the hazards which exist when persons work or
  travel near a highwall or bank and their escape
  from a fall or slide of material could be
  hindered by the machinery and equipment in their
  escape path.

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57.3430 PPM Cont.

• If escape could be hindered, no work or travel is
  permitted. If, however, the machinery or
  equipment poses no hindrance, the standard is not
  applicable. Consideration must be given to the
  height of the wall or bank the distance between
  the equipment and wall or bank the size and
  positioning of the equipment the location of the
  worker in relation to the escape route and any
  surrounding noise levels or distractions which
  could prevent the detection of falling ground.

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57.3430 PPM Cont.

• Where machinery or equipment becomes disabled
  near a highwall or bank, the equipment operator
  can often safely exit on the side away from the
  hazard. If this is not possible, exit on the wall
  side is permitted. Remounting on the wall
  side may also become necessary in order to
  reposition or move the equipment to a safe
  location for repairs.-

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57.3430 PPM Cont.

• -When the equipment is not removed for repair, it
  must be repositioned at the site so that workers
  will not be exposed to fall of ground hazards
  from which their escape is hindered.

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THE END