by H H Dodds 11 August 1953
The phenomenal development and increase in the gold mining and other mining industries in South Africa after the end of the South African war in the early days of the present century (20th century), created an enormous demand for mining explosives. In fact South Africa soon became the largest consumer of explosives in any country in the world.
There were two explosives factories already in existence in South Africa at this time. These were firstly the old factory at Modderfontein near Johannesburg that had been taken over and modernised and expanded by Nobel’s Explosives Co. Limited, of Glasgow, and secondly the dynamite factory at Somerset West in the Western Cape Province that had been erected by the De Beer’s Company to supply them with explosives for their diamond mining.
However, these two factories were unable to cope with the increased demand for explosives in the country, and large quantities had to be imported from overseas.
One the of the largest exporters of explosives to South Africa during the decade immediately before Union was the well-known firm of Messrs Kynoch Limited of Birmingham, England, who were extensive producers of industrial, military and sporting explosives at their two explosives and chemical factories at Arklow, Co. Wicklow, Ireland and Kynochtown in Essex. About this time the Arklow Factory was very fully occupied with the manufacture of explosives for South Africa. Certain essential difficulties were experienced, mainly caused by the very variable weather conditions inseparable from the long sea journey from Britain to South Africa. It was found difficult to guarantee that the explosives after passing through the tropics would on arrival in South Africa continue to comply with the extremely sensitive official “heat test” as it was called, that was rigidly enforced by the authorities to ensure that the explosives were perfectly stable and safe to handle if the necessary care were used.
Another difficulty, also attributable to high temperatures, was the fact that such explosives were liable to show the dangerous quality of exudation, that is that liquid nitro-glycerine might sweat out of its normally dry gelatinous physical combination with nitrocotton and other solid chemical compounds, and thereby make the material unsafe to handle. Kynoch Limited therefore decided to build a factory in South Africa where nitro-glycerine could be manufactured and mixed with the other ingredients to form blasting gelatine dynamites and other commercial explosives on the spot. This implied also the necessity of manufacturing the sulphuric and nitric acids required for converting glycerine into nitro-glycerine.
Alternative sites were considered in Natal, and near Port Elizabeth, and eventually the very favourable grant of land offered by the old Natal Government at Umbogintwini on the South Coast, 15 miles from Durban was accepted. There was also a general concession in railway rates for all imported raw materials, which remained in force until 1951.
Before this was officially announced by the company, certain members of the staff of the Arklow factory, including the writer, were sounded by the management to learn whether they would accept employment at the new factory and soon afterwards extra staff, including Messrs W V Blewett and G Firth, were taken on at the Arklow factory in preparation for work at Umbogintwini.
In October 1908, although the factory was by no means yet completed, it was decided to send out the first batch of production staff from Arklow to South Africam in order for them to become acquainted with the conditions of life in the new country and accustomed to the design and layout of the new plant.
Accordingly in that month the RMS “Kildonan Castle” conveyed the following: Mr J Bower, Chief Chemist, W V Blewett, H H Dodds, G Firth and M A Troy, Factory Chemists, and the following all-Irish contingent of plant operators, R Knott, H White, P Murray, P Cunningham, P Kavanagh, D J Kavanagh and many others.
From Kynochtown and elsewhere came W Weller, C Scorer, A Bodeker and others. Mr J P Udal, General Manager, C S Heaven, Chief Engineer, W Johnston, Foreman Rigger, T M Hoffe, Foreman, and several other mechanics and tradesmen required for building construction work were already here.
Somewhat later came Messrs W A Martin, Explosives Works Manager, A T Scurr, Factory Chemist, W I Taylor, Chemical Works Manger and others. Members on the commercial side of the undertaking in the early days were Mr Gold, a director of the company, T J Greensill, Commercial Manager and C Allbutt, Chief Clerk. These were later replaced by Messrs P J Gorman, Corton and F W Hinchley, also H V Franklin now of Natal Estates Limited. S H Dark and F Hewitt were members of the office staff for many years.
One Sunday afternoon about the middle of November 1908, we arrived in Durban and were very pleased with its appearance. I think it was a much more attractive place in those days than now. It was, of course, much smaller and cleaner and far less crowded, and there were fortunately very few motor cars then. The population of the 1911 census was slightly over 69 thousand and was probably about 65 thousand in 1908.
The Beach Hotel was the only building on what is now the Marine Parade. Below the lower Marine Parade there was a shark-proof bathing enclosure protected by a semi-circular fishing pier. Immediately facing this was Campbell’s Tearoom with wide verandah and balcony overlooking the bathing enclosure. The only other building on the seafront was the municipal bandstand where there were frequent military band performances supplied by one of the British regiments that formed a garrison at Pietermaritzburg. However, it was to be some little time before we saw all this. We were met at the quay by Mr Udal who took us to Galloway House, a well-known boarding establishment that is still in existence on Musgrave Road where the company had booked accommodation for us temporarily. We hoped to have a day to settle down and receive and unpack our luggage and see something of our new surroundings, but it was not to be.
Mr Udal instructed us to be sure to catch the 7.45 a.m. train to Umbogintwini the next morning; we discovered that the return train left Umbogintwini at 5.45 p.m., arriving in Durban at 6.40, so that we saw very little of the latter place until the following week-end.
Mr Udal was a very capable and highly respected manager, and was usually just in his treatment of his staff, but he was very strict.
Umbogintwini and the whole of the South Coast has changed enormously during the past 45 years. In 1908 Umbogintwini was little more than a series of clearings containing partially constructed buildings in a large area of dense virgin bush. There was a small railway station and sidings recently constructed to replace the former primitive ‘halt’ because of the factory building operations; the only dwelling house for miles around was the station master’s house. This house has long since been demolished and replaced, but the second house to be built (in1909) for Mr Cutler, fitter, is still in existence.
The land occupied by the company consisted of 1400 acres of bush extending over the mile and a half width of land extending between the South Coast Road (which was diverted to circumscribe the site) and the Natal Government Railways South Coast line. On the seaward side of the railway there was nothing but practically impenetrable bush.
When manufacturing production began not long after this, first at the acid factory and soon afterwards on the nitro-glycerine plant, both were operated as continuous processes which of course involved night duty, in which the chemical staff took turns in supervision. This was a most eerie experience at that time. After the last train down the coast passed through Umbogintwini station at 6.15 p.m. and until the arrival of the first train at 7.20 a.m. the following day, there was no communication with the outside world by rail or road, or even (at first) by telephone.
Besides the railway the only means of access to the factory was a rough steep foot track following the electric power line and water main connecting with the water supply pumps located on the Umbogintwini river close to the road drift, about two miles from the factory.
One prominent feature of the railway journey was the Umbogintwini bank, a steep incline between Isipingo and Umbogintwini, said to have a grade of 1 in 30, or about the maximum grade possible for a railway not provided with cog-wheels and ratchet rail.
It was very common for trains to be unable to ascend this slope, especially in the early mornings with heavy dew on the line. After several abortive attempts to make the grade, the train, usually consisting of four small passenger coaches would be divided, the first two coaches being taken up to Umbogintwini station first, the engine then returning to collect the other two.
As soon as the passengers realised what was happening there was a rush from the two rear coaches to those in front, so as not to be marooned in the temporarily deserted coaches. A few years later the same performance was still being carried out, but by this time some dwelling houses and a school had been built at Umbogintwini, and the train served to bring children from the neighbouring village of Isipingo to the school. When the division of the train on the hill occurred, there was then a counter-current of school children rushing from the first two coaches to the last two, so that they might have a plausible excuse for postponing for half an hour or more the dreary hour when they were supposed to arrive at school.
Eventually a branch road was constructed from the Umbogintwini river drift to the factory so that it was possible to motor from Durban. This branch road was at first of a strange dark purple colour, having been surfaced with what was known as “burnt ore”, being the residual iron oxide derived from the combustion in the factory of iron pyrites as a source of sulphur for the manufacture of sulphuric acid. It usually had also a distinct odour of burnt sulphur due to a small residue of oxidisable sulphur.
The road from Durban, though rough, was passable for motor cars except after heavy rains, when there was a succession of flooded drifts. The only road bridge on the Natal Coast roads at that time was the Connaught Bridge over the Umgeni river at the northern end of Durban.
Those were the early days of motoring, when tyre covers were not expected to last more than about 2000 miles, and a journey from Durban to Umbogintwini and back without a puncture was considered rather fortunate.
At all events, there was none of the congestion of motor vehicles that makes travel on the South Coast road near Durban so difficult today. Of course, the excellent motor road known as Kingsway that passes between Umbogintwini and the sea today, presenting magnificent views of the coast line, did not exist in those days, and the South Coast road diverged several miles inland of Umbogintwini before re-approaching the coast at Amanzimtoti.
Incidentally several of the factory staff and employees lived at Amanzimtoti in those days, which is much nearer to the factory than Durban.
The chief disadvantage was the very inconvenient railway service with the only practicable alternative to railway travel being a three mile walk along the railway track. Also, there were very few of the amenities of life that are so well provided at Amanzimtoti today.
On several occasions before the construction of substantial road and railway bridges along the coast, Umbogintwini was isolated by floods. One occasion was in 1917 when practically every railway bridge on the Natal Coast was washed away and Umbogintwini was cut off for several days, both telephone and telegraph services, as well as road and railway communication being destroyed.
Supplies of bread and meat were held up and we subsisted largely on stocks of tinned foods and biscuits and poultry for several days. The mailbags were heaved by a powerful nature across the gap in the railway bridge over the raging torrent of the Umbogintwini river.
At first the factory effluents were allowed to drain away into what appeared to be no-mans land at the southern and lower end of the factory area. Eventually however, these acid waters found their way into the Amanzimtoti lagoon and began to destroy the fish and plant life there. This resulted in an interdict against the company and a lawsuit that was adjudged in Pietermaritzburg. The consequence was that Kynochs had to construct a drain leading out to sea to convey the factory waste. This open drain ran parallel with the railway line for a considerable distance until it reached a spot towards Amanzimtoti where a channel could be cut through the sand dunes leading to the sea at minimum cost.
The drain alongside the railway line was at a slightly lower incline than the railway incline going down to Amanzimtoti, consequently a seen from the train it presented the curious optical illusion of water travelling uphill. The writer recollects hearing two lady passengers comment on this saying that “Kynochs must be pumping the water up the drain somehow”.
The principal waste factory product for disposal besides the burnt ore already mentioned, was sodium bisulphate, a residue to nitric acid manufacture as usually practiced in those days. Sodium bisulphate is a very hygroscopic and highly acid and corrosive sticky white lumpy substance, for which practically no use could be found in this country. Evidently the explosives factory at Modderfontein had even greater difficulties in disposing of their sodium bisulphate, since about this time they went to the trouble and expense of railing the material to Natal to be dumped into the abovementioned drain.
Principal products of manufacture
For the first few years the factory was solely employed in the manufacture of mining explosives of various grades and for various purposes, ranging from blasting gelatine through different grades of gelatine dynamites to the powder dynamites. Blasting gelatine, the most powerful explosive then known, consisted entirely of nitro-glycerine gelatinised with about 7% of nitrocotton and was used for the initial breaking of very hard rock. Gelignite, the most powerful of the gelatine dynamites in common use contained from 60 to 65% of nitro-glycerine gelatinised as in blasting gelatine and mixed with 35 to 40% of wood pulp and sodium or potassium nitrate; this moderated the violence of the explosion and reduced the cost. Gelignite became the most widely used of mining explosives. There were other grades of gelatine dynamite of similar ingredients to the above, but mainly containing smaller quantities of nitro-glycerine, such as 50, 40, 30 or 20%. These were correspondingly less powerful and cheaper, being used in lighter work in softer rocks. There were also 15 and 10% nitro-glycerine products, but these did not required the expensive nitrocotton since the proportionately large quantity of woodmeal was sufficient to absorb the nitro-glycerine thoroughly and uniformly to make a dry powder known as a dynamite. The original word dynamite was applied to the first mining explosives made with nitro-glycerine before the gelatinising absorbent, nitrocotton was discovered. Kieselguhr, a highly porous and finely divided mineral was used, though not in itself combustible, and was capable of thoroughly absorbing up to three or four times its weight of nitro-glycerine. However, with the discovery of nitrocotton and its properties, the greater values of gelatinous explosives, and of dynamites containing combustible mixtures for absorbents, such as various forms of cellulose with sources of oxygen such as nitrates were recognised.
Nitro-glycerine was and probably still is, the most important constituent of mining explosives though now partially replaced by other substances. It is made by allowing pure glycerine to react with pure nitric acid in the absence of water. But since water is formed as an essential product of the reaction, it must be removed as soon as formed. For this purpose concentrated sulphuric acid with its intense affinity for water is used, though it takes no direct part in the formation of the nitro-glycerine. Glycerine is, of course, a by-product of soap manufacture and must be highly refined for the preparation of nitro-glycerine; it must therefore pass very stringent tests for purity.
It is carefully and slowly run into a tank containing the requisite mixture of concentrated nitric and sulphuric acids, care being taken to stir thoroughly (usually be means of compressed air jets) and keep the temperature down by refrigerating coils, otherwise the nitro-glycerine may violently decompose or explode.
When the operation is complete the mixture is allowed to settle, when the nitro-glycerine is displaced by the residual acid mixture to form an upper layer of clear colourless or pale yellow liquid; this is made to overflow into another tank by gradually injecting more residual acid from an earlier operation into the lower part of the tank. The nitro-glycerine so obtained is washed several times with dilute sodium carbonate solution and with water until neutral and until it has passed the very strict and sensitive stability tests.
It is then mixed with carefully dried and tested nitrocotton and afterwards with any other required ingredient.
A feature of a nitro-glycerine plant is that each separate operation must be performed in a special building for that purpose and no other. It is located on a slope so that the nitro-glycerine and spent acids can flow by gravity along protected gutters from one building to the next until the process is completed.
Each separate building is built at what is indicated by experienced a safe distance against explosive shock from any of the other buildings, having regard to the maximum amount of explosives permitted in these buildings, and is also protected by a surrounding mound of earth from any direct horizontal hit by debris.
These are only some of the very elaborate safety devices and precautions to avoid explosions and to minimise their destructive effects if they occur. A considerable area of land is thus needed for a nitro-glycerine factory or “hill” as it is commonly called. Although accidental and very violent explosions do occur at times, they are usually at long intervals; they are isolated to one or two buildings and the number of casualties is small. The mixing, cartridging, wrapping, packing and storing operations are also separated over a wide area, and subject to the same protective devices, but on level land, since the products are now solid and have to be transported from one section to the next by tramline.
The sulphuric acid was originally made by what is termed the chamber process, that is by allowing sulphur dioxide gas resulting from the burning of sulphur, or pyrites containing sulphur, to pass into large leaden chambers where it is oxidised and converted into sulphuric acid by reaction with nitric oxide and moisture. The dilute sulphuric acid thus formed was concentrated by passing it in the form of a finely divided spray down a high tower packed with porous acid-resistant bricks and strongly heated by a coke furnace. This was known as the Gaillard process. Later even more concentrated sulphuric acid was obtained by oxidising some of the sulphur dioxide to trioxide with the use of a catalyst of ferric oxide followed by platinum and absorbing the sulphur trioxide by means of normal concentrated sulphuric acid from the Gaillard towers. This process of making sulphur trioxide was known as the “contact” or “Mannheim” process. Later vanadium was used as a catalyst for oxidising sulphur dioxide to the trioxide, from about 1912.
Nitric acid was made at Umbogintwini by the old process of distilling in large iron retorts a mixture of sulphuric acid and sodium nitrate, also known as “Chile Saltpetre”, so-called because of its occurrence in Chile in vast deposits on the dried-up and rainless site of a former sea. Nitric acid distilled over and was condensed in large earthen-ware receivers. The residue in the stills was the objectionable sodium bisulphate already mentioned. This method of making nitric acid is seldom if ever used nowadays – it is usually made by oxidation of atmospheric nitrogen by converting it first into ammonia. Part of the ammonia is oxidised to nitric acid, which is then neutralised by the remainder of the ammonia to make ammonium nitrate.
Effects of the First World War
The World War of 1914 to 1918 greatly affected the Umbogintwini factory. Up till then the factory manufactured and sold exclusively mining explosives except occasionally relatively small quantities of sulphuric acid. During the war, however, the factory undertook the manufacture on a large scale of guncotton for military purposes, eventually making as much as 140 tons per week. Guncotton, which is a highly nitrated cellulose containing about 14% of nitrogen, was exported to Britain, mainly for the purpose of making cordite, but to some extent for naval mines. Cordite is a form of smokeless military explosive made from guncotton and nitro-glycerine into a gelatinous product with the aid of petroleum jelly. This guncotton was made without reducing the continued manufacture of 100 tons per week of mining explosives, so that the production of sulphuric and nitric acids had to be greatly increased also and the factory much extended for these purposes. In the early part of the war there was a serious shortage of glycerine, largely owing to the stoppage of supplies from Continental Europe from whence a considerable proportion of the glycerine used had been obtained. Shortly before the war a large consignment was received from Germany of what was exported as 98% glycerine, but on routine analysis was found to contain only about 10% of glycerine, the remainder consisting of water.
Kynochs created a subsidiary company in Natal in 1910 to manufacture glycerine from whale oil, but it was first found impossible to produce a pure glycerine free from propylene glycol. A large scale explosion, fortunately not attended by loss of life, resulted in 1911 from the nitration of this product, but eventually a sufficiently pure glycerine was made from this source. However, this source of supply was limited for many years.
Later during the war there was a very severe shortage of chemical fertilizers, especially superphosphate in this country, importation being greatly reduced, so that Kynochs were asked to undertake the manufacture of superphosphate at Umbogintwini since they were in a position to do so by supplying the necessary sulphuric acid to convert imported raw rock phosphate into superphosphate. This led to the company becoming permanently an important producer of chemical fertilizers. Other chemicals that were very short in supply because of the war were also produced, such as Epsom Salts, Glauber Salts, Aluminaferric (sulphates of Magnesium, Sodium and Aluminium respectively), hydrochloric acid, hydrofluoric acid, chemical pure mineral acids generally, also hydrocyanide acid for fumigation purposes, etc. etc. In this way the wide range of chemical manufacture now made by the company was first established.
About the end of the war, Kynochs Limited merged their Umbogintwini factory into a new South African company, now known as African Explosives and Chemical Industries Limited, which included also the factories at Modderfontein and Somerset West.
The manufacture of mining explosives was later concentrated at the two last named factories, leaving the Umbogintwini factory free to develop further a number of chemical industries, besides building eventually the largest superphosphate plant in the southern hemisphere. The cessation of explosives was however, a serious blow to the factory at the time, under the prevailing economic conditions.
During the general economic depression after the 1914-1918 war, the future of the Umbogintwini factory was regarded somewhat doubtfully, and the company even encouraged members of the technical staff and skilled workmen to seek work elsewhere if they desired, and provided generous bonuses for those doing so, an offer which the writer accepted and emigrated to America in 1921, returning to South African in 1924. Mr W Helcke was general manager at the time (1921) having succeeded P Udal; after Mr Helcke’s return to Britain in 1922, he was succeeded by W V Blewett, and it was largely due to the efforts of the latter and those of the staff who elected to remain that even a temporary close-down was avoided.
However, subsequent events have shown that there was no need to fear prolonged recession. The excellent factory site at Umbogintwini within easy reach of Durban as the premier port of the Union and a rapidly growing industrial city, and even nearer to the shortest route in the Union from the coast to the rand, will always provide excellent opportunity for enterprising ownership and skilled production to help meet the ever-growing industrial and agricultural chemical needs of the Union.
The writer has pleasure in acknowledging the help of Messrs W G Bates, G Firth, A T Scurr and Miss D Scorer in recalling and revising many of the matters to which reference has been made.