Porto Flavia
Encyclopedia
Porto Flavia is a sea harbor located near Nebida in the Iglesias
comune
of Italy
. Built in 1923-1924, it served as the mineral production hub of Masua in the west coast of the Sardinia
n Sulcis
area. It is named after Flavia Vecelli, the daughter of Cesare Vecelli, who engineered and designed the harbor. The harbor's characteristics make it unique in the world, and at the time of its construction it was an outstanding engineering feat.
, sulphur, barium
, zinc
, lead
, silver
and other metals. Extraction began in 1600, but became economically relevant only in the early 1900s when the mining business in the whole region experienced a quick expansion. The extraction, especially of the coal caves, was operated on a low-technology basis until early XX century. Since late 1800s metal-gathering enjoyed more modern techniques, as it was controlled mostly by rich north-european corporations more willing to commit money in improving the mining efficiency.
In 1922, the Masua mines were acquired by the Belgian Vieille Montagne Company, and exploitation increased with the growing need for zinc and lead for post-World War
reconstruction as well as because of technological advance in steel alloys. The zinc and lead ore was extracted in the mines by male miners (aged 16 and above), processed by female workers and children in a centralized "washing plant" (called Lavatoio), and was finally stored.
Until 1924, sailors from Carloforte moved the processed ore in wicker
baskets placed on their shoulders and loaded their bilancelles (a traditional Sardinian boat design with two lateen
s) to their limits (up to 30 tons per boat). The ore was brought 30 kilometers to Carloforte Island harbor, where it was manually unloaded from the boats. The ore was then stored in the magazines or in the hold of waiting steamships until a full load could be shipped to the foundries in France
, Belgium
and Germany
.
The transport process was costly, slow and dangerous. The bilancelle could not stand stormy seas, especially when loaded with lead, and so the service was discontinuous and the boats commonly sank. Sailors had terrible working conditions with low wages, no rest, and great physical fatigue. In bad weather, up to two months could be needed to fully load a steamship in Carloforte, while in good conditions no less than 7 days were needed: the cost of the wages for so many workers in addition to the much larger cost of the steamship and quay rent made the transportation of the ore a very significant expense in the production process.
. Here, the sea was deep enough and well-protected from wind and waves to allow a safe mooring, while the ore could be loaded from the cliffs by gravity.
After one year of study, he devised a detailed plan to build two superimposed tunnels, each 600 meters long, that were linked by nine huge vertical reservoirs for the processed ore. In the upper tunnel an electric train was used to bring the load the reservoirs: the ore was unloaded by gravity into hatches on top of the reservoirs. In the lower tunnel a conveyor belt received the ore from the reservoirs and brought it to an extensible 16 meter long conveyor belt capable of fully loading a steamship moored at the base of the cliff in about two days. The reservoirs, carved directly into the rock, were capable of holding over 10 thousands metric tons of ore.
Because the tunnel was without angles or trenches, the usual technique for dynamite-drilling was impossible (the crew used those angles and trenches as shelter while blowing up charges just a few meters away). Instead, small cavities were excavated at regular distances to allow the workers to gain cover after igniting explosives. They are still visible in the guided tour.
The workers began drilling the upper gallery, 37 meters above sea-level, with dynamite
and mechanical drills (many mines at the time mostly used pickaxe
s) until they reached the sea. They then hung from ropes and began drilling the lower tunnel from the cliff-face, 16 meters above sea-level, going the opposite direction under the upper gallery. This way, they could dump the removed rocks directly into the sea. Finally, the reservoirs were excavated by creating holes in the basalt
ic rock, starting from the bottom of the cavities and going up. This again eased the removal of rubble, although this procedure was very dangerous. Each storage reservoir was 4 to 8 meters in diameter and 20 meters in height
Venting holes were opened on the side of the galleries. Mechanical iron hatches were installed, along with the electric railway into the upper tunnel. The train brought the ore to the loading hatches of the reservoirs, while in the lower tunnel the unloading hatches fed the ore to the conveyor belt leading to the ships. The belt was covered with a steel casing to prevent the wind blowing away zinc oxide
powder. It was extensible, and retracted after a load was delivered to the ship's hold. The main conveyor belt featured an innovative movable alignment system, designed to reduce the risk of the belt escaping the driving wheels under the pressure of the falling ore. The main belt dumped the ore on the slightly lower extensible conveyor belt, which could be protruded for 15 meters and channeled the ore powder into a vertical shaft going to the hold of a moored ship.
Construction took only two years, ending in 1924, a remarkably short period of time for a work of that size. The ends of the tunnels facing the sea were adorned with concrete towers and decorative nameplates. They were not necessary to the operation, but were asked to be constructed by the owner of the company as a mark of prestige. Vecelli's daughter, Flavia, was born earlier in 1924 and the engineer obtained from the company to name the harbor after her.
Working conditions in Porto Flavia were better than in the mines because of a functional powder removal system, good venting, natural light, top-class machinery and better wages. But there were lethal accidents: one of the more risky jobs was done by the Squadra della Morte (Death Team), a special group of workers who had to enter the reservoirs by hanging from above and removing with poles and picks the ore that got stuck on the rocky walls.
Under normal conditions, the plant was able to deliver over 500 tons of ore per hour to a waiting ship.
Porto Flavia is a UNESCO
-protected site, and is one of the suggested destinations for tours of minerary and industrial archeology sites in the region. Daily tours are held in the tunnel, guided by former workers or mining technicians of IGEA.
Iglesias
Iglesias is a comune of Carbonia-Iglesias province in Sardinia, Italy.-Overview:Situated at 190 m in the hills in the southwest of Sardinia, it was a centre of a mining district, with lead, zinc, and silver being extracted, as well as for the distillation of sulfuric acid.Iglesias'...
comune
Comune
In Italy, the comune is the basic administrative division, and may be properly approximated in casual speech by the English word township or municipality.-Importance and function:...
of Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
. Built in 1923-1924, it served as the mineral production hub of Masua in the west coast of the Sardinia
Sardinia
Sardinia is the second-largest island in the Mediterranean Sea . It is an autonomous region of Italy, and the nearest land masses are the French island of Corsica, the Italian Peninsula, Sicily, Tunisia and the Spanish Balearic Islands.The name Sardinia is from the pre-Roman noun *sard[],...
n Sulcis
Sulcis
Sulcis is the southwestern region of Sardinia, part of the larger Sulcis-Iglesiente region. It is named for the Phoenician city of Sulcis , present-day Sant'Antioco....
area. It is named after Flavia Vecelli, the daughter of Cesare Vecelli, who engineered and designed the harbor. The harbor's characteristics make it unique in the world, and at the time of its construction it was an outstanding engineering feat.
Mining production
The Masua hub was a complex of several mining operations in the Sulcis area, a region of Sardinia rich in coalCoal
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...
, sulphur, barium
Barium
Barium is a chemical element with the symbol Ba and atomic number 56. It is the fifth element in Group 2, a soft silvery metallic alkaline earth metal. Barium is never found in nature in its pure form due to its reactivity with air. Its oxide is historically known as baryta but it reacts with...
, zinc
Zinc
Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
, lead
Lead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
, silver
Silver
Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...
and other metals. Extraction began in 1600, but became economically relevant only in the early 1900s when the mining business in the whole region experienced a quick expansion. The extraction, especially of the coal caves, was operated on a low-technology basis until early XX century. Since late 1800s metal-gathering enjoyed more modern techniques, as it was controlled mostly by rich north-european corporations more willing to commit money in improving the mining efficiency.
In 1922, the Masua mines were acquired by the Belgian Vieille Montagne Company, and exploitation increased with the growing need for zinc and lead for post-World War
World war
A world war is a war affecting the majority of the world's most powerful and populous nations. World wars span multiple countries on multiple continents, with battles fought in multiple theaters....
reconstruction as well as because of technological advance in steel alloys. The zinc and lead ore was extracted in the mines by male miners (aged 16 and above), processed by female workers and children in a centralized "washing plant" (called Lavatoio), and was finally stored.
Until 1924, sailors from Carloforte moved the processed ore in wicker
Wicker
Wicker is hard woven fiber formed into a rigid material, usually used for baskets or furniture. Wicker is often made of material of plant origin, but plastic fibers are also used....
baskets placed on their shoulders and loaded their bilancelles (a traditional Sardinian boat design with two lateen
Lateen
A lateen or latin-rig is a triangular sail set on a long yard mounted at an angle on the mast, and running in a fore-and-aft direction....
s) to their limits (up to 30 tons per boat). The ore was brought 30 kilometers to Carloforte Island harbor, where it was manually unloaded from the boats. The ore was then stored in the magazines or in the hold of waiting steamships until a full load could be shipped to the foundries in France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
, Belgium
Belgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...
and Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
.
The transport process was costly, slow and dangerous. The bilancelle could not stand stormy seas, especially when loaded with lead, and so the service was discontinuous and the boats commonly sank. Sailors had terrible working conditions with low wages, no rest, and great physical fatigue. In bad weather, up to two months could be needed to fully load a steamship in Carloforte, while in good conditions no less than 7 days were needed: the cost of the wages for so many workers in addition to the much larger cost of the steamship and quay rent made the transportation of the ore a very significant expense in the production process.
Designing Porto Flavia
The mines' owner asked the Italian engineer Cesare Vecelli to devise a solution to improve steamship loading time and cost. Vecelli surveyed the coasts of Masua, ultimately finding the perfect spot in the high cliffs in front of the Pan di Zucchero stackStack (geology)
A stack is a geological landform consisting of a steep and often vertical column or columns of rock in the sea near a coast, isolated by erosion. Stacks are formed through processes of coastal geomorphology, which are entirely natural. Time, wind and water are the only factors involved in the...
. Here, the sea was deep enough and well-protected from wind and waves to allow a safe mooring, while the ore could be loaded from the cliffs by gravity.
After one year of study, he devised a detailed plan to build two superimposed tunnels, each 600 meters long, that were linked by nine huge vertical reservoirs for the processed ore. In the upper tunnel an electric train was used to bring the load the reservoirs: the ore was unloaded by gravity into hatches on top of the reservoirs. In the lower tunnel a conveyor belt received the ore from the reservoirs and brought it to an extensible 16 meter long conveyor belt capable of fully loading a steamship moored at the base of the cliff in about two days. The reservoirs, carved directly into the rock, were capable of holding over 10 thousands metric tons of ore.
Construction
A special crew of miners expert in explosives and rock climbing was assembled. They worked in shifts, day and night, to complete the excavations in record time. Despite safety measures being practically ignored to speed up work, no casualties were reported in the building phase.Because the tunnel was without angles or trenches, the usual technique for dynamite-drilling was impossible (the crew used those angles and trenches as shelter while blowing up charges just a few meters away). Instead, small cavities were excavated at regular distances to allow the workers to gain cover after igniting explosives. They are still visible in the guided tour.
The workers began drilling the upper gallery, 37 meters above sea-level, with dynamite
Dynamite
Dynamite is an explosive material based on nitroglycerin, initially using diatomaceous earth , or another absorbent substance such as powdered shells, clay, sawdust, or wood pulp. Dynamites using organic materials such as sawdust are less stable and such use has been generally discontinued...
and mechanical drills (many mines at the time mostly used pickaxe
Pickaxe
A pickaxe or pick is a hand tool with a hard head attached perpendicular to the handle.Some people make the distinction that a pickaxe has a head with a pointed end and a flat end, and a pick has both ends pointed, or only one end; but most people use the words to mean the same thing.The head is...
s) until they reached the sea. They then hung from ropes and began drilling the lower tunnel from the cliff-face, 16 meters above sea-level, going the opposite direction under the upper gallery. This way, they could dump the removed rocks directly into the sea. Finally, the reservoirs were excavated by creating holes in the basalt
Basalt
Basalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey...
ic rock, starting from the bottom of the cavities and going up. This again eased the removal of rubble, although this procedure was very dangerous. Each storage reservoir was 4 to 8 meters in diameter and 20 meters in height
Venting holes were opened on the side of the galleries. Mechanical iron hatches were installed, along with the electric railway into the upper tunnel. The train brought the ore to the loading hatches of the reservoirs, while in the lower tunnel the unloading hatches fed the ore to the conveyor belt leading to the ships. The belt was covered with a steel casing to prevent the wind blowing away zinc oxide
Zinc oxide
Zinc oxide is an inorganic compound with the formula ZnO. It is a white powder that is insoluble in water. The powder is widely used as an additive into numerous materials and products including plastics, ceramics, glass, cement, rubber , lubricants, paints, ointments, adhesives, sealants,...
powder. It was extensible, and retracted after a load was delivered to the ship's hold. The main conveyor belt featured an innovative movable alignment system, designed to reduce the risk of the belt escaping the driving wheels under the pressure of the falling ore. The main belt dumped the ore on the slightly lower extensible conveyor belt, which could be protruded for 15 meters and channeled the ore powder into a vertical shaft going to the hold of a moored ship.
Construction took only two years, ending in 1924, a remarkably short period of time for a work of that size. The ends of the tunnels facing the sea were adorned with concrete towers and decorative nameplates. They were not necessary to the operation, but were asked to be constructed by the owner of the company as a mark of prestige. Vecelli's daughter, Flavia, was born earlier in 1924 and the engineer obtained from the company to name the harbor after her.
Operations
When Porto Flavia became operative in 1924, it slashed ore production costs by up to 70%, allowing Veille Montaigne to gain a strong market share in a short time. The construction of Porto Flavia paid for itself in under two years, and was considered a technical marvel in the minerary business. Other mine operators were not allowed to use the tunnel and harbor, still relying on manual labor or on longer railway routes. The opening of Porto Flavia left many sailors from Carloforte without a job, damaging the nearby island economy.Working conditions in Porto Flavia were better than in the mines because of a functional powder removal system, good venting, natural light, top-class machinery and better wages. But there were lethal accidents: one of the more risky jobs was done by the Squadra della Morte (Death Team), a special group of workers who had to enter the reservoirs by hanging from above and removing with poles and picks the ore that got stuck on the rocky walls.
Under normal conditions, the plant was able to deliver over 500 tons of ore per hour to a waiting ship.
Legacy
Porto Flavia's importance decreased in the 1960s after the decline of mining activity in Sulcis, and it was closed in the 1990s when mineral production in Masua ceased. Today, it is owned by IGEA SpA, a public company charged with the restoration and preservation of the old mining plants.Porto Flavia is a UNESCO
UNESCO
The United Nations Educational, Scientific and Cultural Organization is a specialized agency of the United Nations...
-protected site, and is one of the suggested destinations for tours of minerary and industrial archeology sites in the region. Daily tours are held in the tunnel, guided by former workers or mining technicians of IGEA.