Part 2 CCT Overview
Technologies for Coal Resources Development

1A2. Coal Production TechnologyTechnology Overview

seepage due to higher ground pressure. The mining
machinery is required to have maneuverability to respond tovariations in natural conditions. Utilizing larger-scale mining
machinery to increase the extraction capacity of theequipment is limited by space constraints.
For mining coal deposits near the ground surface, open-cut
mining is used to strip the overburden and extract the coal.
When coal deposits are steeply dipped or composed ofseveral coal seams, open-cut mining is used for extraction. In
this mining method, the overburden is piled in a place where it
will not interfere with the mining work, and a pit is formed in
the ground surface during mining. Horizontal or slightly dipped
coal deposits are mined by the strip mining (side casting)method, in which the overburden is temporarily piled justbeside the mining site and returned to the original site after
the coal has been extracted.

Coal occurs in slightly or steeply dipped beds, or in the formof discontinuous lenses underground. The depth, number andthickness of coal seams vary by region. Coal minedevelopment requires consideration of these geologicalconditions and the state of ground surfaces. Specifically, thequality of coal, the depth, thickness and dip of coal seams,
the presence of faults and folds, and the properties of coalbearing strata substantially affect the productivity and theresource collection rate. The mining method to be used may
also vary due to these conditions. Underground mining
requires the drilling of shafts down to an underground coalseam to extract coal. The shafts may also be used totransport equipment and workers, for ventilation anddrainage, or for prospecting for coal. As mining develops, thedigging area becomes deeper, raising the issues ofmaintaining the mining space, gas emissions, and water
1. Backgroundproductivity while addressing the challenges faced by coalproducing countries. These efforts have led to theestablishment of stable coal production systems and improved
production capability, thus contributing to a stable supply of coalfor Japan. Japan has also extended assistance to coalproducing developing countries for the sound development oflocal coal industries through joint research with localorganizations, aimed at improving coal production technology.

Coal-producing countries in the Asia-Pacific region are facedwith coal mining challenges, such as mining under deeper andmore complex geological conditions. To cope with thesechallenges, while improving safety and productivity, newtechnical measures are required. NEDO and JCOAL have,therefore, carried out domestic and international research anddevelopment on coal production based on technologies
introduced and developed in Japan to improve mine safety and2. Technologies to be developed
To address the challenges faced by coal-producing countries
in the Asia-Pacific region, such as mining under complex
geological conditions while ensuring safety, improved
productivity, and a stable coal supply, novel technicalmeasures are required.

Overview of typical open-cut mining
Strippedoverburden
Coal seam(1) Open-cut mining- Draglines- Power shovels and dump trucks- Overview of open-cast mining- Side-cast O/C
Side-cast strip mining(2) Underground mining- Longwall mining- High-power coal mining machines- Highwall mining (auger mining)

Draglines

Underground mining (headframe)

Power shovels & dump trucks
17Clean Coal Technologies in Japan

Development of a high-power coal mining machine
In order to achieve higher production efficiency in mining hard and thick coal seams, a new high-power multi-motor
coal mining machine was demonstrated at a mine in Australia.

Longwall mining (SD Mining) drum shearer and shield support

High-power coal mining machine (following control function)

Development of a high-power excavator
To improve the efficiency of hard-rock tunnel boring, ahigh-power rock excavator equipped with rock bolts has
been developed.

Highwall mining (steep incline auger mining system)

Drifting road header MRH-S220Development of high-speed manned cars
In underground coal mining, as drifting progresses to include deeper working faces, measures are needed to ensure
the necessary working time in the faces. To increase the efficiency of transportation and shorten the transportation time,
high-speed manned cars with a maximum speed of 50 km/hr have been developed.

High-speed manned cars (former Taiheiyo coal mine)

High-speed manned cars (former Ikeshima coal mine)18