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COMMISSION
  
OF
  
INQUIRY
  
INTO
  
SAFETY
  
AND
  
HEALTH
  
IN
  
THE
  
MINING
  
INDUSTRY 
 
33 
 
during the year 1992 / 93 the total number of fatalities in New South Wales, 
Australia was four.  According to the Annual Report for 92/93 of the Department of 
Mineral Resources, New South Wales, coal production in the State for that period 
was 84 million tons, and the number of persons employed was 15 820 for 91/92.  
The fatality rates in South Africa and in Australia are 0.91 (ten year average, 
excluding explosions) and 0,25 per 1 000 employed respectively.  It is true that the 
proportion of surface mined coal is somewhat higher in NSW than in South Africa, 
but the less favourable underground conditions would tend to compensate for this 
advantage. 
 
The second largest cause of injuries is falls of ground.  The Commission did not 
have much evidence with regard to this problem, which prevents the formulation of 
specific comments. 
 
The COMMISSION RECOMMENDS that this matter be further investigated. 
 
3.3.2  The Explosion Hazard in Coal Mines 
 
Two of the most important lines of defence against coal mine explosions involve the 
avoidance of ignitions of methane, and the containment of the damaging effects that 
can occur if an ignition develops into an explosion. 
 
-prevention of Methane Ignitions. 
 
The evidence before the Commission indicated that the majority of ignitions 
occurred in bord and pillar workings.  These ignitions were initiated almost 
exclusively near the working faces or in the goaf.  It was argued that South African 
coals are harder to cut and therefore there is a greater likelihood that sparks are 
generated in the course of coal cutting.  If a greater frequency of sparking is 
expected in South African collieries during coal cutting then much greater vigilance 
must be exercised to ensure that if sparks do occur, they do not encounter fuel to 
initiate an ignition or an explosion. 
 
The primary site for the prevention of ignitions is the working face.  The greatest 
problem is likely to be encountered at or near the coal faces in bord and pillar 
workings.  Due to the chequer-bord layout the faces are away from the main airflow 
much of the time.  Unless determined efforts are made to achieve improvements, the 
ventilation of these headings is likely to remain inadequate to clear methane and 
dust. 
 
The aspects that require attention include distance from cross ventilation, minimum 
air velocity, height of working, recirculation, air quantity and quality, coursing of air 
from one working face to another and of course, the methane content of the air near 
the cutting picks. 
 
Evidence placed before the Commission and observations during visits appeared to 
indicate that insufficient vigilance is applied by management and the inspectorate to 
ensure the satisfactory control of the ventilation of working faces in bord and pillar 
workings.  Less opportunity arose to examine the measures applied to control 
methane in goaf areas, but history and the evidence of Mr M J Deats of Eskom 
suggested that this problem also requires attention. 
 

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COMMISSION
  
OF
  
INQUIRY
  
INTO
  
SAFETY
  
AND
  
HEALTH
  
IN
  
THE
  
MINING
  
INDUSTRY 
 
34 
-control of Coal Dust Explosions. 
 
The Chamber of Mines in its submission stated categorically that the recent 
explosions which have devastated some of the collieries were methane explosions. 
 
No evidence was presented to support this assertion, which was disputed by others.  
The Commission feels that the possibility of the involvement of coal dust in the 
explosions cannot be excluded.  To explain the largest explosions it is necessary to 
postulate either the presence of a widespread accumulation of methane in a mixture 
with air within the explosive range, or the involvement of coal dust in the 
propagation.  While the former explanation may be true of some of the disasters, it 
would reveal an incredible failure on the part of management if major accumulations 
of methane were the principal fuel of all explosions.  Consequently the contribution 
of coal dust to the severity of at least some of the explosions cannot be disregarded, 
it is necessary, therefore, to intensify measures to prevent the spread of explosions. 
 
The primary measures of protection against the propagation of coal dust explosions 
are; 
 
-the cleaning up of all coal dust in the face area that can be lifted into the air to form 
a dust air mixture.  Only very small quantities of coal dust are required to create this 
mixture; 
 
-dust abatement by wetting; and 
 
-stone or rock dusting so that inert dust is mixed with the coal dust in sufficient 
quantity to make the mixture inert. 
 
In addition to these measures in many countries, especially where longwall mining is 
practised, stone dust barriers or water barriers are also mandated. A notable 
exception in this regard is the USA where such barriers are not prescribed.  In 
Australian coal mines barriers are used in conveyor belt roadways only.  The current 
South African regulations make the use of barriers optional. 
 
The use of barriers has been the subject of much international debate.  There can be 
little doubt that if they can be applied effectively, they are an important defensive 
measure.  The debate has centred around the effectiveness of barriers in particular 
situations.  Experts argue that, where the bord and pillar system is the primary 
method of mining, a multiplicity of drives is available and they are laid out on a 
chequer-board pattern.  The application of barriers is cumbersome and expensive 
and, at the same time, provides doubtful protection.  In the European type of 
longwall mining, where limited numbers of entries (gates) are used, the efficiency of 
barriers is not in doubt. 
 
The COMMISSION RECOMMENDS that:- 
 
-methods of face ventilation should be subjected to an immediate and aggressive review; 
 
-the relevant provisions of US Code of Federal Regulations, Mineral Resources, Title 30 (Part 75 - 
Mandatory Safety Standards - Underground Coal Mines, Sub part D ventilation, para 75.3.) should 
be studied in detail; 
 

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