ANGLOCOAL LANDAU COLLIERY

COMBATING

SPONTANEOUS COMBUSTION

MIDDELBURGWITBANK

KROMDRAAIOPENCAST

PRETORIA

JOHANNESBURG

LOCALITY PLAN

WITBANK

BETHAL

VERENA

N4

N12

N4

GREENSIDE

RLT

KLEINKOPJE

NAVIGATIONPLANT

CLEWER

N

HISTORY OF KROMDRAAI

Known as Coronation Colliery,

Underground mining commenced in 1926,

Underground mining finished in 1966,

Total of 35 million tons mined,

Mined by “handgot” methods.

STRATIGRAPHIC COLUMNTOPSOIL AND SUBSOIL

WEATHERED SANDSTONE

WEATHERED SHALE

SHALE

SHALE

TILLITE

SANDSTONE AND SILTSTONE

NO.2 SEAM

SANDSTONE PARTING

NO. 1 SEAM

2,0

6,0

9,010,5

12,5

17,5-26

19,7

22,423,0

25,726,0

2,2

2,7

2,7

CLAY

TYPICAL PROBLEMS IN THE EARLY DAYS

FACTORS ESSENTIAL FOR SPONTANEOUS COMBUSTION

HEAT SOURCE CARBONACEOUS MATERIAL AIR

LANDAU’S MAIN INITIATIVES WERE TO

REDUCE THE AMOUNT OF AIR ENTERING THE

WORKINGS

METHODS TO REDUCE AIRFLOW

SEALING OF GEOLOGICAL BOREHOLES, DISUSED SHAFTS & SINKHOLES

BUFFER BLASTING BLAST DESIGN-HOLES IN PILLARS, EXTRA

CHARGE IN THICKER PARTINGS SEALING FIRES AND UN-COLLAPSED

PILLARS, BY PUSHING SOFTS OVER THE HIGHWALL

DRAGLINE SEALING HOTSPOTS AS THE COAL IS EXPOSED

DRILLING AND BLASTING

U/G WORKINS

SOFTOVERBURDEN

HARDOVERBURDEN

ANFO

1 SEAM

PARTING

GAS BAG

GAS BAG

2 SEAM

TOP HAT

POSITIONING OF BLAST HOLES

PILLAR HOLESTO FLOOR

INTERSECTION HOLESTO TOPOF COAL

BLASTING PROCEDURES RISK ASSESSMENT ON HOT HOLE

CHARGING DONE IN CONJUNCTION WITH AEL

TEMPERATURE OF EVERY SHOTHOLE IS MEASURED - MAX 60 DEG.

BENCHMASTERS REPLACED CORDTEX DOWN THE HOLE

EVERY HOLE PLUGGED WIT TOPHAT AFTER DRILLING

SINHOLE IN WORKING FACE (BLASTING AREA)

KROMDRAAI COAL RESERVE BLOCKS

NORTH

CENTRAL

SOUTH

EXCELSIOR

SEALING OF HIGHWALL

LARGER THAN NORMAL SAFETY BERMS

SEALING HIGHWALL BY DOZING OVER

HOTSPOTS SEALED BY DRAGLINE

PIT CONDITIONS SHOWING THE WORST SCENARIO

BURNING

ADVANTAGES AT KROMDRAAI

HIGH SOFTS TO HARDS RATIO - GOOD SEAL AFTER BLASTING

THE SIZE OF THE PIT (2.5KM) ENSURES A DRAGLINE CYCLE OF

APPROXIMATELY 3 MONTHS - HENCE THE BUFFER DOES NOT STAND FOR

EXTENDED PERIODS

FURTHER CONSIDERATIONS

DE-WATERING OF U/G WATER BODIES IS SCHEDULED SUCH THAT WATER

REMAINS IN THE WORKINGS AS CLOSE AS POSSIBLE, TO THE MINING WINDOW

CURRENT PIT CONDITIONS BLAST HOLES NOT WARM LESS THAN

4% OVER 60 deg. IN THE LAST YEAR HOT HOLES ARE SEALED AND LEFT

UNCHARGED, MARKED ON PLAN, REDRILLED 1m AWAY FROM PREVIOUS POSITION AND CHARGED WITH NEXT BUFFER LINE. (we have a second chance with buffer blasting)

HOTHOLE CONTROLE CLAD THE SAME DAY FOR BEST

RESULTS DO NOT OPEN FIRES IN OPEN PIT

MINING

QUESTIONS ?