Trial testing document to be saved at ENtexts of today 01

WAZO HILL CEMENT WORKS CONSTRUCTION 1964-1967

“TWIGA” TANZANIA CEMENT CO. Ltd. DAR-ES-SALAAM

Prelude

We settled in the house owned by the Bamburi Portland Cement Co. Ltd. Mombasa that was my new employer. I was appointed as the Chief Structural Engineer and my first job was to look after the construction progress of the new cement works at Wazo Hill. The construction site was some 30km north of Dar-es-Salaam, the capital of the United Republic of Tanzania. My new office room was on the top floor and there were 3 draught boards placed next to windows two of which were occupied already. Windows viewed north onto the factory workers camp and the garden department. The Head office building was a 3-story building incorporated in factory northern fence line and next to the gate house that had two main entrance lanes at each side.

I did not have much time to get acquainted with my new working place and the two draftsmen not to speak about the plant itself either. A few days after our arrival I had to visit the construction site at Wazo Hill in its contract’s fourth months. A well known British contractor MOWLEM E.A. Ltd. got the contract and it was important to learn more about the project I was supposed to supervise for my new employer’s company. Everything was absolutely new to me and it would be good to recollect briefly the political and economical situation of the country where the new cement works were under construction.

The first aerial views eastward of the Wazo Hill Works made in August 1964. In front left is the garage, workshops and stores; at far on top is the main crusher with the sieving plant and bunker.

Political situation

Firstly here a brief report about the geography of the former state of Tanganyika that became known as United Republic of Tanzania (UAT) later. Tanganyika is in the East Africa on western coast of the Indian Ocean. At north of it are Uganda and Kenya; to the west Burundi, Rwanda, and Congo; and to the south Mozambique, Zambia, and Malawi. Within Tanganyika are three lakes: Victoria in the north, Tanganyika in the west, and Nyasa in the south. Mount Kilimanjaro (5.895m) in the north is the highest point of Africa. The island of Zanzibar is separated from Tanganyika’s mainland by a 22ml channel.

The written history starts when Arab traders began colonizing of this region around 700. The Portuguese explorers reached these costal regions at 1500. Portuguese had some control of the Coast only until the 17th century when Sultan of Oman took over power over it. In 1885 the German East Africa Colony was established that encompassed the regions that are now Burundi, Rwanda and Tanganyika. After the end of World War I the former Colony was administrated by Britain under the mandate of the League of Nations and later as a UN trust territory.

The Zanzibar Island has not been mentioned in histories until the 12th century although one believes that there were some connections with the Southern Arabia. Portuguese made the island as one of their tributaries in 1503 and established a trading post there. They were driven away by Oman Arabs in 1698. Zanzibar declared its independency of Oman in 1861 and in 1890 it became a British protectorate.

Julius Kambarage Nyerere (*1922 - †1999) served as the first President of Tanzania, formerly of Tanganyika from the country's beginning in 1961, and retired in 1985. Nyerere was born in Tanganyika to Nyerere Burito, Chief of the Zanaki tribe, and was known by his Swahili name Mwalimu or “teacher” that was his original profession prior he entered into the politics. Nyerere completed his primary and secondary education in Tanganyika obtained the teaching diploma after attending the Makarere University in Kampala, Uganda. After he returned to Tanganyika he taught Biology and English in the Tabora Secondary School. In 1949 Nyerere got a scholarship to attend University of Edinburgh where he obtained his Masters of Arts Degree on Economics and History in 1952. Back in Tanganyika he taught History, English and Kiswahili in a college near Dar-es-Salaam. In 1953 he was elected president of Tanganyika African Association (TAA) that was transformed in 1954 to the politically oriented Tanganyika African National Union (TANU). TANU's main objective was to achieve the national sovereignty for Tanganyika and within a year TANU became the leading political organization in the country.

Tanganyika became independent on December 9, 1961 and Zanzibar on December 10, 1963. Jamshid bin Abdullah, the Sultan of Zanzibar, was toppled by a coup in 1964 so Nyerere instrumented the union between the islands of Zanzibar and the mainland of Tanganyika. On April 26, 1964 the two nations merged by a symbolic mixing of soils and became known as the United Republic Tanzania six months later.

When Nyerere became the first Prime Minister he started with his socialist economic program to be published in the Arusha Declaration on 01.01.1967. He set up the policy of collectivization in country's agricultural system known as Ujamaa or «Family hood». Nyerere’s policies can be characterized as socialistic but he was first and foremost an African, and only secondly a socialist thus he was often called an African socialist. Later he established close ties with China.

The co-operation of Kenya, Tanganyika and Uganda dates back to the early 20th century. The Customs Union between Kenya and Uganda existed since 1917 to that Tanganyika joined in 1927. The East African Common Services Organization (EACSO) functioned from 1961 to 1967 merging the Authorities of Harbors, Railways and Airways of the three states together.

Construction of new Cement Works at Wazo Hill

I had to use EAA (East African Airways) on my first few flights from Mombasa to Dar-es-Salaam to stop briefly on Zanzibar. During this intermediate stops passengers were not allowed leaving the aircraft and any attempt to “smuggle” cloves out of the island was punished severely (even with a death penalty). At those days German advisors from DDR were rather welcome on Zanzibar. I needed a multiple visa for Tanzania that was not that easy with my Yugoslav passport at first. Several days after our move to the house at Bamburi Ljiljana’s and Vesna’s passports were stolen. Soon after we got the tripartite pass of the East African Union (EAU) solving problems of traveling. We would travel through all three states of Kenya, Tanzania and Uganda during the years of our stay in Mombasa without any particular problem.

The International airport was located not far from City centre and company’s driver was waiting for us there already. There was a Cement Silo Station with an adjacent Packing plant in Dar-es-Salaam harbor that was owned by Tanzania Portland Cement Co. (TPCC). The Government owned about 1/3 of its shares in this company. The other but major shareholders were Bamburi Portland Cement Co. Ltd. (Kenya) and the two parent companies Blue Circle UK and Cementia Holding in Switzerland. In future TPCC would also be owner of the new Works at Wazo Hill some 30km north of the City. A well-known contractor MOWLEM UK was on the construction site for some time. Dr. Otto Werner, my mentor for a long time, accompanied me on this trip and we were greeted by contractor’s representatives in two Danish engineers. However we would hear a flood of complains and requests about missing drawings etc. soon after.

The coral pinnacles in the excavation pit for cement silos (Ted Hoskins and Otto Werner) at left and right the group waiting for a chartered plane departure at Mombasa airport in August 1964.

The site of red soil had not been leveled flat and along its eastern edge it dropped of some 10m to a lower flat area that reached up to the coastal line some 2km away. In a few larger excavated pits for structures some kind of white “pinnacles” protruded almost to the site level. These pinnacles were cones of white hard coral that could be removed using pneumatic tools later. Yet, cones were far apart from each other and between were red soil larger patches. Therefore the pinnacles had to be excavated to a depth of uniform coral rock to get a uniform support for individual columns foundations.

I found out that the foundation’s bottom level was arbitrary drawn without any previous soil survey. The site “zero level” was the most important data for any construction. However the arbitrary leveled site was above the set zero level meaning that one would have to carry on with more of site excavation sometime. Only this additional excavation would allow the correct access to all buildings as well as to complete the infrastructure works such as roads, drainage, sewage etc. This would be my first instruction to the contractor as he would be entitled adequate payments for any extra jobs. Some hard learning stood before me for the coming months!

The construction works on a few buildings were well advance or almost in their final stage. The main crusher (for coral rock) with a sieving plant over a bunker was in use already as the contractor started producing concrete blocks he needed for on works. The buildings for stores, workshops and the garage yard were almost ready as to be handed over to the owner’s utilization. As a sudden blow came when the contractor’s site agent told us that the design for infrastructure does not exist yet. Also they did not receive construction drawings for a number of plant buildings so far. Some complains followed regarding the detailing of reinforcing drawings that I did not understand at first. Moreover viewing the contract schedule perfunctorily I thought the contractor must be about 4 month behind the set out time and in that case the penalty clause might have to be applied. The departure time saved us more embarrassments so I returned to the airport bewildered about what I had seen on my first visit to Wazo Hill site.

The excavations advanced for the Raw Meal Silos at left and for the Gypsum Crusher at right.

The excavations continue throughout of September 1964.

Back to the office next day I had to report about my first visit to Wazo Hill to the General Manager (GM) Mr. Ian Roberts or Dick. At first he was stunned by my distressing report not knowing anything about many problems I have learned about. Up to now a locally employed architect has been visiting the construction site and he had to design housing for the new company’s staff as adjacent to the plant. Dick asked me to inform him about my findings so that he could write the site’s report what he was done in the past since. This I had to frankly refuse and asked instead for a secretary to whom I would dictate my report. Dick had to accept my proposal as it became evident to him that a number of serious measures had to be introduced instantly. Dr. Felix Mandl, the Managing Director (MD), was to arrive in a few weeks so Dick did not want to confront him with an embarrassing situation at Wazo Hill. Thus Dick’s decision started an avalanche of changes that would cause a considerable delay in our anticipated return to Europe. Dr. Mandl had envisaged that we would stay in Mombasa for say 3 or to a maximum of 6 months before going to Europe where I was supposed to start a design bureau for the Cement industry.

The weeks passed fast and by end of 1964 I got my own room in the Head office (HO) and also a secretary Mrs. Pereira. She came from Goa (India) like her husband who worked as a civil engineer in Mombasa. Mr. Pereira would join us in a short time after so there was a team of 4 working in the design office that had reorganized to be able to deal with forthcoming tasks. The younger draftsman Anthony de Souza (Tony) was also an Indian from Goa and lived in Kenya for some time. The elder one was Werner Smolniker an Austrian who came to Kenya when the construction of Bamburi Cement Works started in 1954. Smolniker knew Dr. Mandl from previous times when he was working in the Cement industry in Austria. We befriended Smolnikers soon and who stayed in a house next to Dr. Mandl’s one. The later two houses were located at the coastline where as ours was some 50m back inland sited on a coral rock.

Now I should continue my description referring to the development and events linked to the construction works ongoing at Wazo Hill only. The first thing was to prepare a general site plan for the Works that should include all buildings and the infrastructure like roads, surface water drainage, sewage and other utilities. One day Smolniker who was drafting Plant general plant layout told me about the dramatic facts regarding the completion of working drawings. Such drawings did not exist for about one third of plant buildings like the secondary crusher (for gypsum, silicate clay and iron ore), clinker transport, packing plant with cement silos, switch house and water tower. When MD learned about the overall state of design and he asked me to take care about all these deficiencies instantly. In my desperation I called on my mentor and good friend Otto Werner asking for his help urgently. Otto responded positively and offered the help by the many colleagues on the Faculty of Civil Engineering in Zagreb. This cooperation continued on for many years onwards and particularly when I started the design bureau in Salzburg in 1967.

At left the deep pit of the Gypsum crusher and the completed foundations for Raw Meal Silos with the excavated deep pit for the elevator tower by end of October 1964

This was the beginning of cooperation with “Werner’s Group” that had completed the designs for the packing plant and the two silos for cement at first. I decided to deal in our office with the alimentation bunkers for the raw mill and the cement. These bunkers were situated within the crane hall where the construction work had started already. It was best to do the design on spot in close the cooperation with a malcontent contractor by now. One day Smolniker shocked me again in finding out the crusher for gypsum and clay is missing too. The crane hall was situated along the eastern plot’s edge next to a sharp drop of some 10m to a plane below. There was no free space on the crane hall inner side so we had to place the crusher and its hopper at the outer side. Thus an access road had to be constructed along the hall eastern side as it was still enough space across to the plot edge. Although the solution was simple but the crusher needed a deep pit bellow the discharge hopper at road level. The final depth depended upon the elevator footing that had to lift the crushed gypsum or clayey soil over the crane hall retaining wall some 8m above road level. Thus the crusher structure had a very deep pit – almost down to the plane level.

I have visited Wazo Hill almost every week where the Contractor’s Clerk of Works Mr. Ted Hoskins became my best counselor and helped me a lot in getting the project well up to its faster way. Ted introduced me to Norman & Dawbarn Co. who was a Quantity Surveyor (QS) on this project. This kind of services was new to me and it took me some while to adjust to the different contract procedures and policy that differed from the socialistic ones significantly in many aspects. I had to learn fast from mistakes on my first project of private ownership and with Ted’s help and guidance I got hold on this somehow deficiently started Wazo Hill project. The experienced I gained here was the basis for my future project for the cement industries all over the World.

View down on the concrete block making yard close to the sieving plant at left. Seen at right is the inner raw of Crane Hall foundations near to Raw Meal Silos and Kiln foundations seen at top of.

The delayed receipt of detailed reinforcing drawings by the contractor was caused by an almost idiotic conversion of the metric dimensions to the imperial ones. Many of these drawings were drafted in Vienna by a University docent and his draftsmen who were not conversant to inches or feet at all. Thus they drafted everything in metric system (millimeters) to convert the dimension into inches. It started with bar diameters say an Ø20mm bar was not Ø3/4” but an unusual profile of Ø13/16 inch. Most of the problems arose with conversions of the lengths that resulted in some strange broken parts of inch like 7/16 or 23/32 or whatever it came out of an “exact” calculation from millimeters. Of course, Smolniker and Tony had to spend hours to replace all these ridiculous parts of inch to normal ones including the bar diameters. An idiotic and time consuming job!

By end of 1964 I got the project at Wazo somehow on the rail but both MD and GM were of the opinion that I have some spare time. Thus I got involved in some jobs at Bamburi like supervising the Works Building department and the Concrete block plants that run rather erroneously and without proper supervision. Almost at the same time the GM had cancelled the service contract with the architect to whom I was supposed to report but had frankly refused to do. It turned out that the architect did not submit the project for two senior staff houses and two blocks of flats for medium staff members. Then the MD decided that we could produce the drawings for the staff housing at the same time with other work we had in hand. I was getting slightly confused with many projects’ tails hanging around our small staff. The worse of all was their variety and overlapping drafting work that was dictated by the contractor’s urgent needs.

However there were some positive developments that helped to speed up the loose ends say at Wazo Hill. The general survey map of the plot has been completed so I could start with the infrastructure planning at last. First we laid the internal factory roads that enabled access to various buildings and in particular to the stores, workshops and the garage works badly needed already. The overall surface drainage caused a major problem because the crane hall cut off the natural draining direction over the plot edge. Then I had decided to place the main outflow pipe deep enough to be save across the hall’s floor. I did not like this solution but had not other choice. The pipe was situated next to the deep excavations of alimentation bunkers below the dividing wall inside the Crane hall bypassing the deep pit for the gypsum crusher outside of. The outlet pipe deep position provided a good slope for the Works internal surface drainage.

The design and construction problems did not stop yet. The large and heavy foundation rotary kiln foundations did not require a too deep excavation though. The pinnacle’s bases were much deeper than that of required excavation depth so I worked out a new method to create a proper basis for Kiln foundations. One had to cut off pinnacle’s head at prescribed depth, excavated and/or cleaned out the soil in between to be replaced by lean concrete then. The drawback was that such work was not specified in the contract so the QS in charge calculated new and appropriate unit rates that I accepted as the Engineer in Charge. All these procedures were new to me but I was learning more and more as I worked on my first project of this kind and of considerable volume that is value.

From left columns and retaining walls of Crane Hall outer raw, block work as inner shutter for Raw Meal Silo with wall reinforcement and completed deepest pit in coral rock for Gypsum Crusher elevator.

Now the contractor had brought in heavy earth moving machines so one could start with the site leveling and the preparation of road beds. The company contracted a Cessna aircraft with a pilot so the contractor leveled a landing strip next to the site at Wazo. This resulted in a reduction of travel costs as well as of the wasted time making more efficient travels from Mombasa to and fro Wazo Hill. It became easier for me too and I could also extend my staying at the site too. The construction works went on well throughout the whole 1965 so the site looked like a beehive all over.

The top inspectors (Dr. Mandl at right) of the opened Quarry Trench with shovel dredger at rear of left picture and advanced construction of Crane Hall columns inner raw with bunkers at far left. In background are the well advanced Kiln foundations by February 1965.

On the site there were two concrete batching plants and the cement was delivered in bags from the packing plant in harbor. The crushed aggregate came from the newly opened quarry of Wazo plant. At first large quantities of concrete were produced to cast the foundations. One used motor-driven tippers efficiently to distribute the concrete in batches of say 0.5m³ at ground level. However smaller man-pushed tippers could fit on the elevator lifting platform only. The later type of tipper was known as “japanner” as it had a bucket for about 0.1m³ of concrete mounted between two large wheels. A wide concrete surfaced yard was used to stack concrete blocks but also to prefabricate some elements of reinforced concrete needed for say the Crane hall.

Construction progress on site by February 1965: build-up with concrete blocks of internal walls in

Raw meal storage silos at left and Crane hall west side columns and bunkers and Kiln foundations in background at right

The cement works had a central storage facility provided by the process design of that time. The Crane hall was obviously the solution in that raw materials were stocked up at one side where as cement clinker and gypsum were stored separately. The Crane hall design followed a well probed structure type that had the main columns at 8m c/c with retaining walls 8m high in between. The later ones were vaulted and slightly inclined made of concrete block thus forming a barrel shell. The crane beam top was at 12m above the floor on that a crane or more run along the hall on rails 20m apart. The fixing of crane rails had caused many problems before but at this plant the fixation detailing had been used successfully on several other plants already. The crane grab discharged stored raw materials (raw materials like coral and clay, and clinker and gypsum) into the alimentation bunkers of the two mills.

Left the first ever constructed barrel shell roof for the Clinker storage hall in the Cement Works in Beočin (Yugoslavia) in 1925. At right the roof barrel shell concreting of the Crane hall at Wazo Hill mid 1966.

The crane beam had at thick slab to outer side that took lateral loads caused by crane side ways movements. At the same time this slab was the lower cord longitudinal truss between the columns and its top cord was the edge beam cum gutter for the barrel shell roof. The Crane Hall roof was structurally a barrel shell spanning 24m with ribs at 4m c/c on top of. The barrel shell has been cast in situ on top of a shuttered platform supported on trussed scaffolding that one moved along on crane rails. There was an expansion joint 8m apart in the shell thus at the center of Crane hall columns. The top ribs had been concreted after the hangers were placed through each holding a pair of tie rods of Ø30mm. The tied rods (with turnbuckles) took the full tensile strain of the shell lateral thrust when the shutter platform had been pulled to the next bay of 8m. This barrel shell roof was the classical structure invented by Mr. Hubert Spannring long before the design theory had been worked out in 1950s. The first barrel shell roof of 15m span had been constructed on a storage hall for the Cement Works at Beocin in the former Yugoslavia in 1925.

The large building attached to the Crane hall accommodated the Raw Mill at one side and the Cement Mill on the other one. This was not a common solution as these two types of mills normally do have separate buildings often far apart from each other now a days. In this particular case the wide building had a roof of trussed arches spanning of 24m placed 4m c/c cast in situ. For the roof cover one used prefab slabs of 50cm width the same as for the Crane Hall. Subsequently the joins between slabs were cast in situ as well as the wider joint on the arch itself making the whole system a barrel shell at the end. The lower cord of arched truss was the tie of the barrel shell. This type of a barrel shell roof system yet as a prefabricated method has been developed by Otto Werner in the early 1950s. It was used on many industrial buildings with long spanning roof that could be supported at the edge of a building only.

By end of 1964 several buildings got out from their foundation pits. Columns stood out like spikes all over the site that had leveled in general in accordance the plant layout prepared in the design office at Bamburi. The contractor started erecting several elevators that would enable lifting of materials to the upper floors of buildings. I was glad to see that the contractor used ACCROWS UK steel forms and scaffolding instead of timber that was a rather rare commodity in Africa. However this site had some more of surprise ready for me.

Aerial view on the Crane hall columns up to crane beam level and bunkers almost ready by May 1965 left and at right completed HET and kiln house, bunkers in Crane hall and cement silos by September 1965.

The foundations for two Raw Meal Silos were completed and the contractor was ready to start with the shuttering for circular wall on one of. Masons started using concrete blocks to form the internal shutter for that wall. I was told that this method was specified by the contract (?) so I started an enquiry whose brilliant idea was to do it. Back to Bamburi I had got the answer from Smolniker who told me about that the first silos here were build that way in 1952 here. I had stopped that practice instantly as rough blocks’ surface impedes the flow of substance in the silo. This was particularly the case with the fine grinded raw meal to be homogenized by strong air flows.

The Raw Meal Silo consisted of two compartments: a lower for storage and an upper for blending. In the blending silo the fresh milled meal was homogenized and when processed it was flowing down in the lower section to be used as for the kiln feed. Then after the contractor used ACCRORWS circular double steel shuttering of 4ft height that slid up the wall at say two days intervals. The building of an internal wall with concrete blocks was a tedious and time consuming process so the contractor happily accepted my instruction to stop it. The two raw meal storage silos were the last built in this old fashioned method. Luckily I never got any rebuke from Dr. Mandl who obviously agreed to that former method when he started building the Bamburi plant in 1952.

The crane rail bedding ready for casting in and movable roof shuttering moved to the north end of Crane hall at left. At right completed the Crane hall raw materials storage areas with bunkers seen from a crane.

By mid of 1965 Martin Froehlich, a mechanical engineer who escaped from the East Germany, was appointed as the Technical Director and moved into his house first. Mr. O’Shea came as the second to become as Company’s Chief of Account. Now ready flats were steadily occupied by future plant supervisors and a few erectors from various plant suppliers. Some of plant buildings were ready for the machinery erection and Martin got some headaches to coordinate and organize the erection works with the building contractor finishing a few of his “building tails”.

Martin Froehlich and Ted Hoskins inspect progress of works on Blocks of flats left and the Senior staff house allocated to Martin as the General Manager of TPCCo.

The construction progress was good on the two senior staff houses and two blocks of flats. Thus I informed Dr. Mandl on his visit to Wazo Hill by end of 1965 that the plant’s new staff would be able to move in a few weeks time of. I could submit him the finished design for factory’s infrastructure that included a cost estimate prepared by our QS. The estimate was based upon contractor’s unit rates and the costs were about T£30.000. It came like a shock to MD as it was an additional expense of 10% on the contract sum. We had a long discussion with a few reprimands to me (not be neither the first nor the last ones!) I got the permission to spend T£15.000 only. Therefore I decided to build so much of infrastructure as possible with that amount that resulted mainly in a reduced finish road surfaces. The road was constructed from the gate house leading to stores, workshops and garage workplace. Another short branch was completed as the access to Packing plant and the front of new Head office being under construction now.

By end of 1965 the Governments of China and Tanzania agreed upon a project to build a normal railway track from the harbor in Dar-es-Salaam to Lusaka in Zambia. Soon Chinese engineers were looking for a reliable cement supplier and new Works at Wazo Hill were their obvious choice. There was a dead-end of East African Railways (EAR) narrow track at the military barracks close on the road to Ubungo. One envisaged hauling bagged cement on trucks to a chosen nearby station site. At the station bags would download on belt conveyors to either stacked or directly loaded into wagons fed by an automatic loader. The whole process required little of human power as it had an automatic movable loader arm that could feed 3 wagons stationed there. A packing machine could be installed inside the building later.

The Ubungo Railway loading station from left: the roof scaffolding, placing and fixing of reinforcement on the folded roof slabs first ever constructed in East Africa.

One of the requirements was a minimum of columns in the two compartments that width was 16m and 14m respectively. There were two railway tracks for a total of 6 wagons and all of had to be plied by the loading arm from above. The movable loading arm was heavy machinery hanging on two rails on that it moved along the wagons. I decided to design the roof as folded plates that structural system was my specialty and certainly nobody build something alike in East Africa yet. The span of 14m with some movable loads underneath was a real challenge. When I finished the calculation it proved that the folded plates were the right choice from material and cost point of view. By end of 1966 the contractor finished the Ubungo Loading Station and the machinery subsequently has been installed. The Loading plant started working when the bagged cement was delivered from Wazo Hill plant. A few months later the bag loading system functioned perfectly. So far nobody could understand how that roof of folded plates of 8-12cm thickness could carry such heavy machinery hanging on that long span.

At left view on the movable shutter for the Crane hall shell roof including the longitudinal truss girder on top of the crane beam. At right view from left: Heat exchange tower, Mills building and Crane hall

Despite all setbacks it looked like that the plant might go on trial production some time in last quarter of 1966 already. Then in May Dr. Mandl visited the site again and became so furious seeing that a part of road surfacing was completed only. At first I swallowed a hard clump not to answer “that is what one gets for T£15.000” but as the conclusion I got a free hand to complete the infrastructure as estimated for. I could reduce my visits to Wazo Hill that suited me well because I was heavily involved with the large construction works going on at the Bamburi plant where a major extension was well underway already.

The plant at Wazo Hill was the first Rotary kiln with a Heat exchange tower (HET) to produce the clinker in a dry-process. The general manufacturer was KHD Cologne, W. Germany and the kiln calculated production was 600 t/d of clinker. Thus the plant capacity was estimated making 175.000 tones per annum for a working period of 275 days. Imperatively we had to consider the possibility of doubling the Works capacity when designing the plant’s structures to be necessary in the nearer future. At that time one did not provide the central electrical control facility so there was one central electric switch room only. Thus the electrical control panels were placed separately at each of plant’s sections along with its machinery controls that were handled pneumatically.

The aerial view southwards shows the construction progress by end of 1965. At right is the building accommodating the garage, workshops and stores. Road construction just started.

The lifting of heavy machinery parts was the real problem provided there was no heavy mobile crane available. Thus one designed two cantilevers on top of the HET to that one fixed heavy joists with a system of pulleys. A wide opening was left in the roof of Kiln house through that one lifted the cyclones on HET appropriate floors. The kiln sections were lifted the same way to be moved into right position on a sledge gliding on rails fixed on top of kiln foundations. The constructed kiln house roof was the last of its kind as it was useless in a tropical country. On some other buildings cantilevered steel joists with pulleys had been fixed temporary to winch up various parts to appropriate floors. To incorporate an obligatory lifting system on all buildings accorded with manufactures was the essential experience for me in future.

The assembling progress is well on of the Rotary kiln and the cyclones in Heat exchange tower in December 1965. The roof of Kiln house is still open but various trial runs are due to start soon.

The mechanical and electrical engineers started assembling the machinery and other equipment subsequently to builder’s completion of any of the plant buildings. Any plant section had to go through a number of running tests first. By autumn of 1966 the whole plant was ready to start the full operational runs. However there were continuing break downs here and there in various sections that became a real nuisance. Of course the employed local labor was not used working in an industrial complex of this size and complexity yet. The General Manager Martin Froehlich had installed three light bulbs on top of the Heat exchanger tower. Thus he could see the lights from his house even at night – green meant plant runs smoothly, yellow there is minor stoppage somewhere in a part of and red meant that the main process system came to an abrupt stop. All the troubles seemed to be more of a persona’s kind of matters than being caused by the plant equipment as such. Martin went to the Minister for Industry to seek an advice and got a straight forward answer to bring in the witchdoctors to exterminate the bad spirits out of the plant.

The Railway loading station at Ubungo completed by mid of 1966. The loading into wagons started soon after the plant went into trial production. At right seen is the movable loading boom

The Managing Director at Mombasa Cement Works Dr. Felix Mandl could not believe to such an advice and asked his good friend the President of Kenya Jomo Kenyatta for his views to. After Kenya got its independence known as “UHURU” in 1964 the President Jomo Kenyatta requested rebels of Mau-Mau movement to abjure their oath to it. He was determined to stop all kind of movement’s atrocities and any mores linked to the black magic with it. Therefore Kenyatta was somehow hesitant about giving any counsel of suggesting instead to seek the advice from his counterpart that was Julius Nyerere the President of United Republic of Tanzania. Julius Nyerere had a nickname “Mwalimu” (The Teacher) so his advice should have to be considered as final to call the witchdoctors or not. Some times later Martin went to see the Minister again to ask for the guidance and instructions regarding this rather sensitive matter. At the Ministry he obtained a sort of cryptic directive coming personally from Mwalimu the President saying to proceed as pleaded for by the Workers Union of Tanzanian staff in the factory. Consequently Martin instructed the Workers Union representatives to proceed on accordingly finding the witchdoctors that would get off the bad spell and spirits hovering over the new Cement Plant.

A number of local witchdoctors came to view and tour around the cursed plant some days after. At the end of they tour they agreed their magic powers are too weak for such a great job. At last they decided to call in the greatest magicians living in the region of Morogoro who then willingly accepted this task as the bush drums informed later. A few days later a number of fairly mystifying looking men arrived followed by an entourage of helpers. Their Chief in charge accompanied by few Unionists met Martin to whom they submitted a list of items that would be needed for the ceremony. At the end of a rather long list also were two living oxen to be required for their rite too. The company had to provide a specific quantity of linen in different colors, a lot of crushed maize corn known as “posho”, several pints of “pombe” that is the fermented coconut milk – all should be used in the exterminating process of bad spirits.

The assembling progress is well on of the Rotary kiln and the cyclones in Heat exchange tower in December 1965. The roof of Kiln house is still open but various trial runs are due to start soon.

The magicians went around the site searching out every of Baobab trees in circumference of the plant nearer area. They placed the appropriate donations for demons under each of the Baobab tree according to the ritual. As the quantity of endowments did not suffice at first more linen, posho and pombe had to be purchased hastily. The Chief magician made a small hut of colored linen looking like a shelter in that he placed a handful of posho and a cup with pombe on top of a spread white linen sheet. Shortly before sunset two oxen were brought in close to the Heat exchanger. First the helpers broke the oxen’s knees so that it could not run away. Then the neck artery was cut open and the gushing blood collected in larger bowls. This gruesome process lasted quite some time until both oxen bled entirely out. Afterwards the animals were slaughtered and butchered cutting the meat into smaller pieces to make the stew for all who attended the rite. Everybody working in the factory was invited to attend that whole ritual rite except for females who were not allowed to be present at all.

Seen at left is the top storey of Mills’ building with the assembled Electro filter and the Heat exchange tower left of. Raw meal blending & storage silos (two storage silos only at back) are shown at right.

The witchdoctors took the bowls with animal blood and smeared a patch on each of the plant buildings. The patch size apparently depended upon the importance of a particular building as considerate by the Chief witchdoctor. We could not envisage why the largest patch was on the Heat exchanger building – certainly it was the most important and largest one in the factory. After sunset most of the Europeans left this congregation that continued to enjoy the stew and even more of pombe long in the night. A few days after this eventful ritual was done something unbelievable happened. All the plant machinery was running almost smoothly. The green light on top of the Heat exchanger tower shone green for days without turning to yellow or even red. It seemed like that the “bad spirits” have been appeased and that the plant future was the most promising one.

The construction works are completed of the two Cement silos at left and the Mills’ Building (for cement and raw meal) and the Heat exchange tower shown at the right picture

In the past months the contractor MOWLEM pulled out from the site completing all the works under the contract including the new Head office building. The QS had submitted the Final Bill of Quantities (BofQ) that included the total amount due to the Contractor and the list of payments received up to date. There were two subtraction amounts to be considered first of was the Withholding money payable to Contractor after warranty time expires. The second amount would be a rather disputable one as it dealt with the contractor’s negligence to complete the works in time agreed upon in the contact.

In the Rotary kiln and the Heat exchange tower started the trial runs in July 1966 as seen at left picture. Clinker transport, Water treatment plant with tower and Switchboard house are shown at right.

Thus it was necessary to call for a meeting in presence with Dr. Mandl so I invited Mr. Bridle, the Director of MOWLEM (EA) Ltd. to be our guest at Bamburi. The guest’s room had to be made ready so my wife checked the bed thoroughly before putting bed sheets on etc. To her dismay she found dozens of geckoes’ eggs placed underneath in the opening of the mattress’s cover. Our daughter collected all these eggs because geckoes were a real nuisance because their vast number. Geckoes were hiding almost everywhere and left their black droppings ubiquitously at any place even on ready food plate etc.

We had a pleasant evening and Mr. Bridle commented Ljiljana’s dinner after that talked long into night sitting on the verandah enjoying the moonlit sea view. We warned Bridle jokingly about possible geckoes visiting their egg laying places in that he would sleep. The next day at Bamburi’s HO was not to be as pleasant when talks stared on the final BofQ and the payments due to the Contractor. We could agree on all items except for the T£8.000 estimated as the negligence because of delayed completion. At this critical moment Dr. Mandl appeared like “Deus ex machina” in the room and invited Mr. Bridle for a word in his office. Some minutes later both returned announcing that the argument has been settled by reducing the disputed amount to T£4.000. Everybody was happy about the outcome and we ended the contract with a lunch in a Mombasa’s renowned restaurant.

The official opening of Tanzania Portland Cement Co. Ltd. was fixed for February 8, 1967. The chosen company’s trade mark was the “TWIGA” meaning the giraffe in Swahili. I got an idea to have a sculpture of the giraffe made out of terrazzo pieces to be fixed at the entrée of the new factory’s Head office. Our architect Tibor Gaal, an émigré after Hungary upraise in 1958, made a sketch 1:1 scale of a giraffe with a height of about 2,5m.

An employee in Bamburi Works’ Building department Italian Fabrizzi was the right specialist for this kind of a job. He made a number of pieces out of the giraffe sketch each about 60cm long. The pieces were cast with brown stone that was then polished in terrazzo art technique to comply exactly with the sketch drawn by Tibor. Each of the pieces had cast in pins on the back side that would enable the fixing on a wall later. Fabrizzi also made a number of slabs in black-white terrazzo technique as to emphasize a natural background.

At left Tibor and Zvonko go up the staircase, Martin and Tibor with the TWIGA sculpture at entrance hall of the Head office. Seen at right is the Water treatment plant and its Water tower.

When everything was ready the sculpture TWIGA was assembled on a grassy plane in front of the window of Dr. Felix Mandl room on first office floor. I went to call Dr. Mandl to look out of his window to see the “giraffe” laid out on the grass. On my way in Dr. Mandl’s secretary warned me that he has a VIP visitor in his room. She announced my coming first and then went to the window herself to view the sculpture.

Dr. Mandl stood up somehow reluctantly but seeing the giraffe laid out on grass got so furious and started scolding me angrily how could I dare to spend so much money on this “object”. At first I stood there stunned and shocked! Luckily for me the VIP guest, who was Dr. Mandl’s best cousin, as well as the secretary were both so enchanted with the TWIGA. They saved my skin for sure! After a while Dr. Mandl agreed that we could fix temporary that “object” until his final scrutiny when he makes the inspection of the Head office at Wazo Hill next time. I left his office happy about the outcome thanking heartedly my saviors. I explained also that the costs of making the “thing” were almost none and that TWIGA sculpture we have considered it to be a present to the new Works.

Then every part of the “object” was carefully packed and shipped to Wazo at next occasion. Few days after Fabrizzi went to Wazo to supervise the fixing of all parts on the wall at the Head Office entrance hall. Additionally Tibor Gaal asked a line to be incised in the wall above the sculpture itself and to paint it in black. The incision would symbolize the silhouette of Kilimanjaro against the bluish-grey wall paint. Next Dr. Mandl inspected our piece of art showing a rather stern mien at first. After a while he ordered two of the black-white slabs to be removed. Then he left us standing there somehow puzzled but happy that the “giraffe” may remain where it was fixed now.

The Head office building is ready for the opening ceremony – at left the northern front and at right the western front with carports. Note the folded plates design used for the cantilevered entrance to the Office building and as the roof over carports.

There was one more technical problem to be solved about the sewage system prior to the official opening. All users within the plant and in all residences were linked by already placed-in pipes up to the outlet that ended at the plain below the factory. Close to the later one ended the plant surface drainage outlet too. I choose for to treat the sewage effluent with the aeration system that consisted of two shallow ponds. To activate the fermentation process in the first of two ponds it was necessary to throw in a dead cat (it is true so no laughing, please) when the sludge got to an appropriate level. One had to wait to until the level got to say 60cm high so that the fermentation process could start when one threw a “dead cat” in that took several days of waiting though. The second pond got filled up by the overflow from the first one what did not matter as it was meant for the final aeration cum evaporation only. For that did not have wait at all. It was essential to maintain the sludge level at say 60cm in the first pond what was not so easy because of the low quantity of effluent from the housing estates. It helped to add some outflow from the water out of the plant cooling system and from the surface drainage for a while at least.

On January 1, 1967 the Government of Tanzania issued the Arusha Declaration proclaiming the Nationalization of all foreign assets like those of banks, industries and private enterprises. Several BPCCO senior staff members and their spouses were invited to the ceremonial sight to be held at Wazo Hill on February 8, 1967. We arrived a day ahead of and stayed in the Kilimanjaro Hotel at Dar-es-Salaam to overnight. The opening ceremony was scheduled for the late morning and a large crowd gathered in front of the new TPCCo Head office. The President of United Republic of Tanzania Julius Nyerere “Mwalimu” arrived with a large entourage that included several ministers and high ranking army officers too.

In his opening speech Mwalimu (The Teacher) said that the new and big cement factory will produce cement for the State of Tanzania from now on. According to the Arusha Declaration the factory belongs to the Peoples of Tanzania now. Following this rather chilly opening speech Dr. Mandl had reiterated in fairly strong words saying that he had experienced such nationalization some time ago meaning that in Yugoslavia. Then he suggested that the President would certainly be wise enough to keep the experienced expatriate technical staff until Tanzanians learn how to operate this complex industry for the good of their country.

Of course the opening ceremony continued in a somewhat depressed mood with guests sightseeing the plant in guided small groups. All systems worked to their best and the green light was on! On the other hand I had won my “prize” when the guests gathered in the Head Office foyer and commended the exceptionally captivating TWIGA sculpture to Dr. Felix Mandl. I never heard any word about the TWIGA from him later at all.

The Main entrance to the Wazo Hill cement works of TPCCo Dar-es-Salaam at left and the Gate house on the day of the official opening February 8, 1967.

Light meals and drinks were served in a few offices but there was no excitement like during the extortion of bad spirits several weeks ago. Most of the guests dispersed soon after Mwalimu left including his followers and we had to hurry to the airport to catch the flight to Mombasa. This was the last time the new Works at Wazo Hill in such a good working condition. However clouds of dramatic political changes in Tanzania obscured its future already.

Epilogue

By end of February 1967 we left our house in Bamburi for good. We were due to travel via Rom to Salzburg (Austria) and settle there where we would stay for the rest of our life time. The parent company Cementia Holding AG in Zurich wanted to set up there a design bureau for the cement producing factories and associated usage works. I would organize that office named Cementia Industrieplanungs AG (CIPAG) in Salzburg. I was in charge and head of through 20 years until my retirement in 1987.

Blocks of flats are occupied as well as junior Staff houses on the plane below the Works in 1966.

The Tanzanian Government paid out the foreign shareholders. Subsequently it entered a new agreement with Cementia Holding AG for Technical Management only. Martin Froehlich remained at Wazo Hill until the second kiln line had been assembled. CIPAG produced all the building drawings for that first extension of TPCC and the 2nd rotary kiln went into production by end of 1971.

The TWIGA cement works under full steam as from early 1967. At left view from the entrance on the main building: Heat exchange tower, Mills’ building and Crane hall in background and at right the southern end portal with the clinker storage area.