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GROUND CONTROL

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THE STUDY OF THE EARTH IS CALLED GEOLOGY. THE SOLAR SYSTEM INCLUDING EARTH WAS ... PORPHYRY--DISSEMINATED COPPER MINERALS IN A FINE GRAINED IGNEOUS ROCK MATRIX ... – PowerPoint PPT presentation

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Title: GROUND CONTROL


1
GROUND CONTROL
  • BASIC GEOLOGY, MINING METHODS AND GROUND CONTROL
    HAZARDS
  • UNDERGROUND

2
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.

3
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

4
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.

5
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.

6
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.

7
  • 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

8
  • 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

9
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.

10
UNDERGROUND MINING TERMS
11
UNDERGROUND MINING METHODS
  • ROOM AND PILLAR
  • LONGWALL
  • CUT AND FILL
  • STOPES
  • BLOCK CAVING
  • SQUARE SET

12
CAUSES OF UNDERGROUND GROUND CONTROL PROBLEMS
  • BLASTING PRACTICES
  • FAILURE TO SCALE LOOSE GROUND
  • WATER EFFECTS
  • GEOLOGICAL--FAULTS, SEAMS,OR POOR GROUND

13
FAILURES AND GEOLOGY
  • Underground
  • Roof falls
  • Span
  • Discontinuities
  • Rib rolls (falls)

14
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.

15
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

16
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

17
PREVENTATIVE MEASURES CONTINUED
  • Scaling
  • Factors to consider
  • Scaling Vs. Bolting
  • Two methods of scaling
  • Manual (hand) - equipment, location, technique
  • Mechanical (remote) - safer, sensitivity

18
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

19
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.

20
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

21
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

22
Precautions- Surface Only
23
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.

24
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.

25
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.

26
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.-

27
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.

28
THE END
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