A CAJM article showing the effects of chrome mining dust on the health of the miners' lungs

Gelfand, M.

Morton, S.A.

Central African Journal of Medicine

English

IDS OpenDocs

The Central African Journal of Medicine
t
Editor:
\ /
MICHAEL GELFAND, C.BE., M.D., F.R.C.P.
Assistant Editor: 
JOSEPH RITCHKEN, M.D.
Volum e Sixteen  
JANUARY - DECEMBER 
1970
Salisbury Rhodesia
T h e  Central African
J ournal of Medicine
Pneum oconiosis in  the Chrome 
M ining Industry of Rhodesia
BY
MICHAEL GELFAND,
C.B.E., M.D., FJR.C.P., D.P.H., D.M.R.
Professor of Medicine (with special reference to Africa), 
University College of Rhodesia;
AND
S. ARCHIBALD MORTON,
M.D., C.M., M.S., F.A.C.R.
Visiting Professor of Radiology, Salisbury, Rhodesia, and 
the American University of Beirut, Lebanon.
Chromite is the only practical source of the metal 
chromium. It is ideally a simple oxide of iron 
and chromium (FeCr20 4), but most chromite 
mined is in fact chrome spinel in which Ai and 
Mg are replaced by Cr and Fe in varying degree.
Chrome ore deposits result from crystal dif­
ferentiation in ultrabasic magmas. For this reason 
they always occur as seams, pods or lenses within 
serpentine and related rocks which are the altered 
derivatives of dunites, peridotites and pyroxenites.
In Rhodesia the seam type of deposit is repre­
sented in the Great Dyke, an ultrabasic body 
some 300 miles long, which in places has six or 
more parallel, flat-dipping seams superimposed 
on one another. Each seldom exceeds a foot in 
thickness, but extends for thousands of feet along 
strike and in depth. They are mined in those 
favourable areas that are close to rail. The pod 
and lens type of ore bodies are found at Selukwe, 
Mashaba and Belingwe in serpentines of much 
greater age than those of the Dyke. The country 
rocks are consequently much more disturbed and 
silicified. Usually free silica is not a constituent 
of serpentine except in very minor amount as 
secondary opal veining. The pods and lenses may 
have all dimensions measuring hundreds of feet, 
so that while being very considerably thicker than 
the seam type, they are not as extensive laterally 
or in depth.
M i n i n g
In mining the narrow seams of the Great Dyke, 
dust generation is minimal. Most of the drilling 
is done in soft serpentine using rotary coal bits. 
In stoping the reducing system is followed. Some 
three feet of serpentine is excavated from above 
the chrome seam, leaving it exposed on the floor, 
from which it is later popped off.
Mining at Selukwe is, in respect of dust forma­
tion, more akin to standard mining methods as 
applied in gold and copper mines, because a
M arch, 1970 PNEUMOCONIOSIS IN CHROME MINERS T h e  Cen tra l  A frican
J ournal  of M ed ic in e
much larger proportion of hard rock must be 
pneumatically drilled and blasted than in the 
mines situated in the Great Dyke. All drilling 
is wet and normal dust suppression techniques are 
employed.
Permissible D ustiness
The yardstick used in Rhodesia is 300 particles 
per c.c., but the average is considerably below
this.
Sources of Dust and Means of Suppression
Along the Great Dyke rotary drilling and mini­
mum dust generation is supplemented by good 
ventilation both natural and mechanical. At the 
Selukwe deposits the following means are 
adopted:
(a) After blasting, the re-entry time for a 
worker is four hours to allow for the air 
to be replaced by fans. The face of the 
tunnel or excavation is subjected to a fine 
spray of water for 15 minutes before the 
re-entry of persons.
(b) Shovelling also exposes the shovellers to 
dust, and to counter this the rock pile is 
wetted down.
(c) Small mechanical loaders create about 
three times as much dust as load shovel­
ling; there again the rock is wetted and 
sometimes an atomising spray is fitted on 
to the front of the loader.
(d) In  scraping operations, when the rock is 
removed by a type of steel grab hauled 
along the ground collecting broken rock, 
the rule is for the rock to be wetted and 
for persons to keep away as far as possible.
(e) When the rock is tipped from trucks into 
an excavation, which forms a - collecting 
point for the hoister unit, a device for 
hoisting to the surface, water sprays are 
used and also doors which enclose the 
dust after rock has been tipped so that it 
can be drawn off into flannel bag filters 
by a fan, thus eliminating the hazard for 
persons working at the tip.
(f) Stopers or those excavators underground 
from where the mineral-bearing rock is 
removed are subjected to wetting down at 
the working face and adequate means are 
taken to disperse the dust from drilling.
(g) Fans on the surface allow fresh air to be 
drawn through the workings and the foul 
air to be exhausted, while small auxiliary 
fans underground ensure the distribution 
of air to all working places in need of it.
Clinical F indings
In the chrome industry 27 miners who only 
worked in the chrome mines and exposed to dust 
were compensated for pneumoconiosis or for 
tuberculosis with or without pneumoconiosis. Of 
this group, only six were accepted as having 
uncomplicated disease of the lungs due to the 
inhalation of the dust. Four of them were graded 
Stage I pneumoconiosis, one as Stage II and one 
as Stage III (Figs. 1 and 2).
Symptoms in the six cases were:
Shortness of breath ......................    5
Cough ................................   3
Pain in chest ................................   1
Haemoptysis .........................................  1
Loss of weight .........................................  0
Mucopurulent sputum ......................  1
Signs were few, for in these six cases one case 
is reported as having rhonci and in another 
crepitations (Figs. 3 and 4).
In all six cases, however, the expansion of the 
chest as measured with the measuring tape was
reduced.
Number .....................................................  2 4
Amount of expansion in undress ...  0-1 1.1-2
The lesions as determined radiologically were 
mostly present in the base or towards the middle 
zones with a tending to spare the upper zones.
Fig. 1—Chrome: first stage pneumoconiosis lesions basal; 
service, 120 months.
58
March, 1970 PNEUMOCONIOSIS IN CHROME MINERS T h e  C en tra l  A fr ic a n
J ou rn al  of M e d ic in e
Fig. 2—Chrome: first stage pneumoconiosis; service, 108 
months.
*
Fig. 3—Chrome: hard nodules plus ground glass. Second 
stage service, 204 months.
Table I
Distribution of Lesions 
R L
3 2
3 3
4 4
The months of service of these six cases showed 
a varying influence of time before they retired 
because of symptoms.
Table 11
Number ...  1 3  0 1 1 0
Months of
service ...  1-100 101-200 201-300 31400 401-500 500+
Of the 27 cases, 21 were considered to have 
tuberculosis, but it was difficult to state definitely 
how many had only tuberculosis and those who 
were also affected by chrome fibrosis.
The symptoms mentioned by these 21 cases
were:
Cough ...................................................  20
Pain in chest ....................................  8
Shortness of breath ................................ ' 9
Loss of weight ....................................  12
Haemoptysis ....................................  5
Sputum positive for tubercle bacilli ...  16
Mucopurulent sputum ......................  13
The degree of expansion of the chest wall was 
restricted in all cases as shown in table.
Table 111
Range of Expansion in 21 Cases of Chrome 
Cases with T uberculosis
Number of cases ...  5 14 2 0
Expansion in inches   0-1 1.1-2 2.2-3 3 +
Fig. 4—Chrome: third stage pneumoconiosis; service,
24 months.
59
The lesions when tuberculosis was present were 
mostly found in the upper zones.
Table IV
D ist r ib u t io n  of  Le s io n s  in  21 C ases w it h  
T uberculo sis
V ol . 16. No. 3. M arch, 1970
R L
14 11
12 15
8 10
X -R ay F in d in g s
The X-ray findings in pneumoconiosis in 
chrome miners has recently been described by 
Sluis-Cremer and Du Toit (1968). In our six 
cases there did not seem to be any pattern that 
would distinguish a chrome pneumoconiosis from 
the usual appearance of silicosis with nodules, 
infiltrates, “ground glass” areas and increased 
lung markings. The nodules were perhaps a little 
finer and harder than in the other dusts, but there 
was no distinctive pattern in the lungs. The hilar 
areas were not involved. The degree of pneumo­
coniosis did not exceed Stage II and there was no 
pleural thickening or calcification. Dr. I. C. 
Gilson, Head of the Pneumoconiosis Research 
Unit of the Medical Research Council of Great 
Britain, who kindly commented on these six 
films, classified the lesions as:
1958 I.C .O . C la ssific a tio n  
3/3t 2/2t
2/2t 2 /lm
3/4N l/2m
C o m m e n t s
One of the earlier references to involvement 
of the lung by chromium was Mancuso and 
Huefer (1951). They described a spotty but not 
nodular pneumoconiosis. On X-ray the changes 
in the lungs consisted largely of an ill-defined 
mottling.
Sluis-Cremer and Du Toit (1968) have de­
monstrated that miners working in chrome mines 
in South Africa develop radiological changes 
which consisted of nodulations and is/ typically 
of a very fine type and that it usually appears 
first in the right upper zone, but may be very 
diffuse.
Besides  ^ the fine nodulation, sparse, short, 
linear opacities of similar density to the nodules 
may be seen, and when the changes are marked 
the extreme lung fields are apparent, although 
there is a tendency for the apices to be spared. 
It is suggested that the nodulation is more radio- 
logically opaque than in simple coal miners’ 
pneumoconiosis. Occasionally the nodules may 
be somewhat larger, reaching up to 2 to 3 mm. 
in size.
The hilar shadows do not usually show any 
change radiologically, but in others the hilar
shadows may be increased, although not as strik­
ing as occurs in silicosis.
Pleural thickening is also an uncommon mani­
festation of this form of pneumoconiosis.
In none of the cases described by Sluis-Cremer 
and Du Toit was shortness of breath complained 
of, and physical signs were few. In our cases 
preliminary symptoms were mentioned, but 
physical signs appear to be minimal, except re­
stricted expansion of the chest.
S u m m a r y
(1) Inhalation of chrome dust can lead to 
pneumoconiosis and six cases are described of 
miners who had worked only in this industry.
(2) Symptoms include shortness of breath.
(3) The radiological changes include fine nodu­
lations, increased lung markings.
REFERENCES
Sluis-Cremer & D u T oit, R. S. J. (1968). Brit. J. 
Indust. Med., 25, 63.
M ancuso, T. & H uefer, W. C. (1951). Indust. Med. 
Surg., 20, 358.
Acknowledgments
We wish to acknowledge the help we received 
from Mr. B. Davey, Chief Government Mining 
Engineer; Mr. M. G. Benham, the Ventilation 
Engineer; Mr. A. I. Bliss and the ladies on his 
secretarial staff, Mrs. V. A. Melville, Mrs. 
Z. E. L. lackson and Miss C. B. lohnny for their 
invaluable assistance.
T h e  Central African
J ournal of Medicine
6 0
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Pneumoconiosis In The Chrome Mining Industry Of Rhodesia

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Pneumoconiosis In The Chrome Mining Industry Of Rhodesia

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