Famous Mineral Localities: THE TREPCA MINE STARI TRG, KOSOVO

Jean Féraud and Gani Maliqi and Vjollca Meha
Mineralogical Record

Jun 30, 2007 20:00 EDT

INTRODUCTION

The famous old Trepca (pronounced "Trep-cha" or "Trept-sha") lead-zinc mine lies near Stari Trg village in Trepca Valley, Kosovo, in me middle of die Balkans. Since 1999, Kosovo has been under die interim administration of the United Nations. It is a landlocked, very small territory (11,000 km^sup 2^, one-fiftieth the size of France), bordered by Macedonia, Albania, Montenegro and Serbia proper. Kosovo is "looking for a common European future and the country's political climate is now stable, safe and strong" (Ceku, 2005), but life there nevertheless is hard; the Gross Domestic Product is only 1,000 Euros per person. The people of Kosovo are proud and hard-working, and they have a long mining tradition. They are doing their best to restart the economy of Kosovo, and particularly to revive their mines, most of which were flooded or otherwise rendered inactive during the war. These mines are now open to foreign capital, and their potential is great-particularly die Trepca mine, with its famous mining and mineralogical museum.

The United Nations currently considers the official Kosovo name of the mine to be "Trepca, Stan Terg." The previous name of the mine under Serbian administration was Trepca, Stari Trg, which is the designation still used in all the mineralogical treatises and museums of the world. Therefore, both terms will be used in this article.

HISTORY

The history of the Trepca mine and of the surrounding region is long and rich, and culminates in me etimologic-political-economic imbroglio which has resulted from the recent war. In attempting to understand the present confusion it would be wise not to place too much faith in claims made on various passionate Internet sites which have proliferated since 1999, as these are creations of interests which seek to manipulate the present situation to their respective advantages. What follows is an objective summary of events during the many centuries in which mining of metals has gone on at Trepca.

Ancient Beginnings

The word "Trepca" occurs very early in written records. Perhaps it derives from two words in the extinct Illyrian language, "tre," meaning "three," and "psha," meaning "furnace"; in mat case me word may signify "three ore-smelting furnaces." A more poetic theory is that the word derives from an ancient legend and refers to women preparing for a wedding. According to the legend, the parents of a beautiful girl who was to be wed adorned her from head to foot with gold and silver on the day of her wedding. "Trepca" from then on denoted the gold and silver adornments of girls at weddings, and it signified beauty.

Mining of the Trepca deposit during Roman times may have occurred but is conjectural. Roman mining of other ore deposits in the Balkans, in particular in Kopaonik and Kosovo, is attested in texts and confirmed by discoveries of Roman oil lamps in some of the old underground mine workings, and by the existence of huge Roman-era slag heaps at Srebrenica, to the northwest of Trepca, at Rudnik and Socanica to the north, and at Grecanica to the south. Texts carved on Roman ruins refer to the assignment of a Roman procurum metallorum municipi at Socanica, where a Roman lead sarcophagus has been found. Probably the Romans were greatly interested in alluvial gold deposits like the Lece deposit (Dusanic et al. 1982, and Dusanic, 2003).

Following Roman times the region was colonized, influenced, or dominated politically by ever-changing populations. The long history of the successive influxes of Byzantine, Bulgarian, Serbian, Albanian and Turkish peoples helps explain the cultural mixing and the legacies of old grievances which underlie the chaos of the 1990's.

The Middle Ages

The first definitely known phase of mining (for silver, lead and iron), beginning in 1303, was intense. Almough probably not yielding as much silver as did the nearby mines of Novo Brdo and Rudnik, the Trepca mine did answer to the needs of Serbian suzerains to fund their military activities; for example, Trepca silver financed the building of fortresses all along the Ibar Valley against the Ottoman threat. Meanwhile the silver of Novo Brdo and Rudnik, extracted from argentiferous lead ores, was used for coinage by successive despots: the first Serbian silver dinars were made at these mines. In 1412, despot Stefan Lazarevid instituted a mining code in a very well written document which specified mining regulations, rights, and obligations, and described mining techniques, in great detail.

A colony of settlers from the coastal town of Dubrovnik lived in Trepöa during the 15th century, and the role of Dubrovnik businessmen in the management of the Trepca mine and in the trade in Trepca ores is attested by texts dating from that time. Numerous experienced Saxon miners were brought in to work at Trepca. Today, the tall ruins of St. Peter's Saxon basilica, dating from the 14th century, may be seen between the Stari Trg miners' village and the open pit The walls of this basilica were originally covered by beautiful frescoes, some of which are still visible. A proposal to restore this still-impressive building has just been submitted to the European Commission and to the Council of Europe (Vidishiqi and Mehmetaj, 2005). In the slope between the basifica and the bottom of the open pit, at the base of some rocky gossan outcrops, it is still possible to see the collapsed entrances of ancient, very narrow mine workings covered by vegetation. Another very old stope and shaft are still open above the open pit, amid the bushes on the rocky slope.

In 1936, some very old underground workings at Trepca yielded interesting remnants of tools which have not yet been scientifically dated but which probably come from the 14th or 15th century. These archaeological finds were examined by Harold Abbott Titcomb (1874-1953), a mining engineer and passionate amateur archaeologist, who was a close friend of Alfred Chester Beatty, chairman of the Trepca mining company. Titcomb reported on many artifacts from medieval mining at Trepca, including an axe "made of nickel and steel" found at 200 meters depth-possibly hammered out of a nickel-iron meteorite. In die Trepia mining museum one may see a few very old tools, most of which came from die Artana mine (Novo Brdo). One is a small wooden shovel composed of a round handle IS cm long and a bucket 30 cm tall; another is a kind of spoon, 15 × 40 cm, made of wood, which possibly was used to scrape ore.

On June IS, 1389, on die Kosovo plain 30 km southeast of Trepca, die Serbian army was overwhelmed by die Turks in the Battle of Blackbirds Field (Kosovo Polje). Following this event a Turkish kadi was installed at die Gluhavica mine near Novi Pazar, but it seems dut for die Dubrovnik mine properties a kind of Turkish protectorate was established, widi die overlord to whom die Trepca mine men belonged, Shala e Bajgorës, retaining some independence. Historians do not record any interruption in Trepca ore production during mis period.

Generally, in die mines of Kosovo, ore extraction was hampered by anarchic management and by die flight of qualified miners, widi die new Turkish supervisors disregarding representatives of die Serbian mine owners and endeavouring to prevent silver exports. However, by 1455, die date of die lurks' conquest of die last areas of Kosovo which had remained independent, Turkish administration of die mines was functioning radier well. The Turks improved die old Serbian mining code, and diey very actively worked TrepSa and outer mines for metals from which to make coinage and weapons. But 1685 saw die beginning of a rapid decline of mining in the Balkans- even at die famous gold, silver and lead mines of Novo Brdo. Today die most impressive relics of die period of Turkish rule are die ruins of a mosque 1 km from the Trepca mine, along me road to Melenica.

The Mid-20th Century

We read nothing more of die Trepca mine until 1925, when die Serbian province of die newly created Republic of Yugoslavia was opened to foreign investors. French mining companies having focused on the copper deposit at Bor, the British company Selection Trust sent its best geologists to select the most promising targets for mining. Selection Trust at this time was a "junior" company, i.e. a small one, but it would soon become a large, "major" company. It was created in 1913 by Sir Alfred Chester Beatty (1875-1968), an American-bom mining engineer whose fabulous life story is told by Lawton (1987)-see the summary in the sidebar.

Alfred Chester Beatty had the genius to select experienced geologists who quickly went on to discover profitable ore deposits in Siberia, along the west coast of Africa, in Northern Rhodesia and in what was then Yugoslavia. The engineer Harold Abbott Titcomb served as a consultant from 1925 to 1932, and excellent work was done later on by Charles B. Forgan. In 1926, Selection Trust signed a contract with Radomir N. PaSic (pronounced "Pashitsh"), son of the former Yugoslav prime minister Nikola Pasic, inaugurating a large regional exploration program with geologic mapping as well as sampling and drilling in the old underground workings at Trepca. The results made clear the huge potential of the ore deposit. On December 9, 1927, in London, a subsidiary of Selection Trust called Trepca Mines Limited was capitalized for £1,789,028. A mining concession was granted by Serbia on March 1, 1928. The company survived the 1929 stock market collapse without difficulty, and the Stan Trg mine opened in 1930 on the site of the medieval openpit mine. "Stan Trg" represents a phonetic distortion by Kosovar shepherds of "Stari Trg," which means "old place" or "old market." The geologist Friedrich Schumacher restored the correct term-Stari Trg-in his memoir of 1950.

The Stan Terg mine quickly reached a production level of between 600,000 and 700,000 tons of ore per year, widi die annual metal output between 50,000 and 60,000 tons-figures which would never again be matched after 1939. From 1930 to 1940 the mine yielded 5.7 million tons of ore, and the on-site flotation plant produced 625,000 tons of lead concentrates, 685,000 tons of zinc concentrates, and 444,000 tons of a mixed concentrate of lead, copper and pyrite. By 1936, however, Trepia Mines Ltd. was in need of more capital. The sale of 4,500,000 shares to new stockholders at 5 shillings per share, mosdy in March 1936 and March 1937, raised £1,125,000. Wim mese new funds me company invested in new equipment and built a lead smelter at Zvecan in 1940.

During mese years preceding World War ?, Germany bought 40% of me ores produced at Trepca. After me Germans seized me mine in 1941, Hermann Goering's Reichswerke Company managed me facilities largely as a slave labor camp, producing batteries for German U-boats. Many Trepca miners were fighters in die Yugoslavian resistance movement during me war. In 1946 die Tito government nationalized die Trepca mine and smelter, together widi all other mines which had been owned by me company. Between 1945 and December 23, 1948, Trepia Mines Ltd. was liquidated and its assets were split between me British and Yugoslavian governments (Dauti, 2002). Numerous webpages are available on me Internet providing lawyers widi reference case histories regarding die liquidation of Trepia Mines Ltd. and the sharing of its assets by me British and Yugoslavian governments, together with judgments concerning private persons involved. These cases set a precedent for world jurisprudence concerning cross-border insolvency issues, liquidation of assets of overseas companies, and entitlement to interpreters in civil matters (cf. New Zealand Law Commission Report 52, 1973).

After 1948, the Mining, Metallurgical and Chemical Conglomerate of Lead and Zinc, Trepca (Rudarsko MetalurSki Hemijski Kombinat Olova i Cinka Trepca) became one of the most important mining complexes in the Balkans. It consisted of several groups of mines. In the north was Crnac and Belo Brdo (whose ore was treated in the Leposavic concentrator), and the exploratory workings at Koporic and Zuta Prlina. In the center of the region was Stari Trg and the Tuneli i Pare concentrator. And in the south and southeast (towards Pristina) were Artana-Novo Brdo, Hajvalija and Kisnica-Badovac, served by the Grecanica concentrator. The complex as a whole yielded an astronomical 60.5 million tons of mine-run ore containing more than 8% lead and zinc, half of which production came from Trepca. This is one of the largest PbZn ore districts in Europe, having produced nearly 3 million tons of lead and 2 million tons of zinc; its silver production has been assessed at more than 4,500 tons. Its present remaining reserves are impressive, although the figures, once calculated according to the criteria of a state-controlled and centrally planned economy, must now be drastically recalculated in terms of profitability in a free-market economy.

Since 1975

This great mining complex, which at its peak employed 20,000 people and produced an important part of the mining income of Yugoslavia, began around 1975 to go into major decline. The problems included obsolescence of the facilities, neglect of maintenance, failure to reinvest funds, the absence of control over ore production and grades, and the theft of equipment, sometimes of whole workshops. Half-hearted attempts at privatization came to very little. The decline accelerated in 1990, when Belgrade revoked the autonomy of Kosovo, Albanian workers left, and ethno-political tensions increased. During the Kosovo war which began in 1998, Trepca and Mitrovica, where the ethnic populations were highly mixed, were among the most grimly contested territories. It was even rumored that hundreds of Kosovar bodies were burned in the furnace of the lead smelter (an investigation by French police found no evidence for this claim).

The arrival of KFOR (the NATO-led international military force responsible for establishing and maintaining security in Kosovo) and the separation of the belligerent parties in June 1999 led to a de facto partition of the mining complex. The northern mines came under the control of the Serbs. The southern mines, which had been flooded, were seized by returning Albanian workers who, however, could not restart production immediately. In the center of the district, KFOR promoted the resumption of production at Trepca and Mitrovica, and the flooded Trepca mine was dewatered. But a French-Danish environmental appraisal of the sites revealed such an accumulation of polluting substances around the two smelters that die civil administrator, Bernard Kouchner, ordered in August 2000 that operations be stopped immediately. Since then, Trepca has been on stand-by, its two smelters destroyed. There are claims on various sides concerning the debt from previous bank loans and die legal ownership of mining rights, and mere is even a rumor mat British interests have demanded an indemnification for the former nationalization by Tito.

To crown it all, mere was a website report (Tanjug, 1999) that on September 18, 1999, the mineralogical museum of the mine was plundered by diieves benefiting from me confusion. However, fortunately, we can report that this news was totally false and mat die museum collections have been preserved.

Audiorities are now cautiously optimistic that restoration of mine production to its former level may be possible. With the approval of all concerned parties, die United Mission for Kosovo (UNMIK), which rules this area for die time being, has launched an important program of technical and economic appraisal in all of die industrial sites of die complex. In August 2000 this program was subcontracted to die G?? (Interim Team for Trepca) consortium, composed of me American Morrison & Knudsen-Washington Group, Boliden Contech, and TEC Ingénierie, a French society of me Eramet group. In August 2005, thanks to die energy of mine management and of me workers, ore production was resumed in me TrepCa mine and the zinc concentrator was restarted. Trepca has obtained an exploration license, and an exploitation license is under discussion, as is die question of how best to attract private investors.

GEOLOGY

History of Published Works

The geology of Trepia is fairly well understood but not yet fully assessed. Excellent studies done between 1930 and 1940 by die geologist of me mine, Charles B. Forgan, were published in 1950, as was me work of Friedrich Schumacher, but during die following 50 years no comprehensive, detailed, well-illustrated study of die giant deposit has appeared. During mis interval the known extent of die orebody as traced along die dip has doubled. The workings now reach to 900 meters below the surface! AU die publications issued since 1950 are short interpretive syntiieses for eitiier die ore deposit or for die whole mineralized belt (Jankovié, 1978, 1984), guidebooks, short accounts of official visits, or detailed publications devoted to a particular topic, such as the innovative stratigraphie datings by Klasic et al. (1972), boldly interpreted by Strucl (1981). An excellent PhD dissertation was written (in Serbian) in 1978 by Aleksandar Topalovic, but diere exist only a few printed copies, available only in geoscience libraries in Belgrade. The only piece of this work mat has been published is a very pertinent map of the orebodies which reflects die high quality of die whole diesis (Topalovic, 1980).

Studies of me mineralogy of Trepia were published over a long period following me pioneering work of Friedrich Schumacher (1950, 1952). Professor Ljudevit Bario of the University of Zagreb deserves me gratitude of die scientific community for his numerous publications, particularly tiiose describing die discovery of vivianite and ludlamite at Trepöa (1953, 1954, 1965). Among noteworthy later publications are those of Slavoljub Terzic et a/. (1975), on die discovery of cosalite; Mirjan Zori (1991) and Vladimir Bermanec et al. (1995), on the discovery of chUdrenite; and works by other scientists including Vladimir Zebec and Vesna Srot. Concurrently with these scientific advances, the beautiful microphotographs of Werner Lieber, particularly as seen in the Mineralogical Record, enlightened Western collectors concerning the "magic" of Trepca specimens, and promoted interest in mineral pangeneses at the locality.

The doctoral dissertation of Gani Maliqi (2001 ), followed by the work of Tmava and Koliqi (2003) and others, has opened the way to a major increase in knowledge about the geological framework of the deposit At die same time, the work of Hashim Këpuska and others (1998-2001), presenting results of geochemical analyses of rare metals (Sn, In, Bi, etc.) in the ore minerals, sheds light on the geochemical nature of the Trepca ore deposit and his block diagrams enable geoscientists to visualize the deposit clearly.

Structural Framework

The Trepca mine is located in die Vardar zone, a nappe of folded and overthrust rock units within the Dinarides Alpine Belt The Vardar zone consists of a Paleozoic basement a Jurassic sedimentary cover, and overthrust Cretaceous ophiolites. Post-tectonic magmas (granodiorite and dacite-andesite) intruded die assemblage during die Tertiary period. The Trepca ore deposit consists of a series of manto orebodies and minerali zed skarns w ithin die sedimentary pile (known as the Stari Trg Series), below a thick layer of volcanic tuffs and ignimbrites of Tertiary age. More precisely, within die Stari Trg Series die orebodies are intercalated between thick marbleized limestones at die bottom and titick schists at die top; in some places along die stratigraphie contact diere is an intercalated layer of quartzite. The contact is folded in an anticline, die northwest-southeast axis of which plunges 40° towards the northwest

Along die crest of die anticline, at die contact between die schists and the limestones, a volcanic chimney was emplaced: the chimney, measuring 100 × 200 meters in oval cross-section, consists of a pipe of trachyte or dacite surrounded by an explosion breccia. It is this chimney which controlled the distribution of mineralization. A manto layer of ore between 30 and 60 meters thick has wormed its way into the schist/limestone contact along the sides of the volcanic pipe, with a few discordant oreshoots which were formerly explored by small prospects in the neighborhood of the Trepca mine.

The granodiorite which now makes up the Kopaonik Range ascended during the Miocene period. The magma body was also die source of trachyte and dacite plugs and pipes intruded into the upper crust leading to the formation of skarns witii garnet pyroxene, amphibole and magnetite in the Trepca orebodies. Within the host rocks, hydrodiermal mineralization was accompanied by propylitization-sericitization, silicification, carbonatization, pyritization and kaolinitization. On the summit of the mountains all around TrepCa, a very important period of extrusive felsic Tertiary volcanism is represented by a large sheet of pyroclastic rocks, especially ignimbrite. This ignimbrite is also present in the deeper levels of Trepca mine, where it appears as a veinlet a few centimeters thick within the breccia which forms the root of the trachyte pipe.

Ore Emplacement and Mineralization

For the most part the Miocene-age Trepca ore deposit is hydrodiermal (both mesodermal and epithermal), but it also includes replacement-type skarns. Isotope analyses suggest that domes ascending from anatexis zones within the lower crust and the upper mantle exerted strong thermal and structural influence; however, ore deposition occurred at the subvolcanic level and at shallow deptii. Such a geological setting, with a hydrodiermal plume of magmatic origin mineralizing carbonate host rocks within favorable hydrologie and tectonic traps, looks very similar to the Kipushi model and to some of the orebodies of Dalnegorsk, Russia and Zletovo, Macedonia.

The volcanic breccia is mainly composed of fragments of schist and phyllite; fragments of trachyte and of limestone constitute no more man 2% of its volume. Dissolution structures are common in the schist fragments and even more so in the limestone fragments. Within the massive limestones (and marbles) hosting the oreshoots on bodi sides of the chimney, hydraulic breccias are very abundant. Therefore we suggest tiiat the explosive character of the breccia was associated with the high content of mineralized fluids around the chimney; because of this high hot water content, there was a strong dissolution process all around the chimney and along all the contacts with the impermeable schists. Such hydraulic brecciation suggests the "maar"-type explosions at the bottom of trachyticvolcanic chimneys when they encounter the water table.

During the Tertiary Alpine Orogeny, water heated by the magmatíc intrusions percolated down through the rocks and took abundant metallic ions into solution. When these waters re-ascended, they were blocked by the impermeable "roof formed by the thick schists. Their high temperature and aggressive chemical properties enabled the solutions to attack the limestones below the schists, digging out huge solution cavities. Gradually, salts precipitating from the solutions coated the walls of the cavities, and where voids remained, large crystals grew. The metallogenetic classification of Trepca (as given in the GIS databases on the Internet) as a hydrothermal/ replacement deposit is not complete: the deposit should also be considered a karst deposit trapped under an unconformity.

Thus, the formation of the ore deposit at Trepca is largely understood: formation of karst caves by the corrosive action of metalliferous hydrothermal solutions, deposition of ore minerals, formation of ore shoots in a hydrogeological trap, and skarn formation controlled by a volcanic pipe. But the origin of the metallic elements in the underlying magma is still conjectural. Since it is known that volcanogenic sulfides are commonly present in massive deposits in belts of ophiolitic rocks, it could be that such a deposit existed at depth in this case, giving up the metals to hydrothermal solutions during the tectonic processes accompanying the subduction of one crustal plate under another.

A related problem, perhaps, is one concerning the ages of the rock units around the mineralization. In fact, no one really knows whether the schists are older than the limestones or vice versa. Until 1973, geologists assumed that the Stari Trg Series sedimentary sequence was Silurian-Ordovician, but in that year Yugoslavian geologists found fossils (conodonts) in the sequence which suggest that some of the limestones could be of Triassic age (Topalovic, personal communication, 1973). What had been thought to be the bottom of the sequence may well be the top! How may this overthrust and distorted zone between the African and Eurasian Plates be accounted for? Instead of an anticline, the purists speak cautiously of an antifona. And if the limestones are Triassic, then, as Strucl (1981) has suggested, the Trepca deposit is a very early manifestation of the mineralizing processes which generated stratabound lead-zinc ore deposits all along the Alps (e.g. Mezica, Raibl, Salafossa, La Piagne, Largentière, Les Malines, etc.).

It is intriguing, and surely of interest to mineral collectors, that none of me common Trepca specimens showing stalactites of carbonates overgrown by sulfide crystals have so far shown axial canals in the carbonate stalactites to give evidence of water dripping from ceilings of caves. This implies that the karst cavities were totally flooded and that their walls were overgrown by sulfides not in void spaces but under a water table. The aumors would like to hear of any Trepca specimens of this type which show axial canals.

MINERALS

More man 60 mineral species have been found at Trepca (see Table 1 ). Naturally, most of these species do not occur in the deposit as collectible crystal specimens. Without doubt, me locality's most beautiful specimens are those in which crystals of sulfides widi bright metallic or adamantine luster are combined widi vitreous or pearly crystals of quartz, dolomite, calcite or rhodochrosite. Of the Trepca sulfides, galena is probably the most interesting because of its great variety of habits, even if the galena specimens generally are not as magnificent as are many from Dalnegorsk, Russia or the Madan district, Bulgaria. Arsenopyrite and sphalerite are also found as excellent crystal specimens in the deposit.

The major Trepca species of collector interest are briefly described below.

Andradite CaFe^sup 3+^^sub 2^(SiO^sub 4^)^sub 3^

Among the skarn silicates, andradite is the best crystallized, occurring as colorless to greenish brown and dark brown crystals to 1 cm which display 110 and/or 211 forms. The other skarn minerals have not been found as attractive specimens.

Aragonite CaCO^sub 3^

Aragonite is not as common at Trepca as calcite, dolomite and rhodochrosite. It forms colorless, transparent crystals and aggregates of crystals to 3 cm long.

Arsenopyrite FeAsS

Arsenopyrite occurs commonly as short prisms widi flat, diamond-shaped 012 faces. These crystals average only a few millimeters long but can reach 5 cm. Epitactic growth on galena and marcasite is common (Zebec, 1975, 1978). Rarely, cubo-dodecahedral galena crystals rest in the middle of arsenopyrite crystal faces. In some specimens the arsenopyrite crystals form mosaic-like sheets of lozenge-shaped faces; much more rarely the species is seen as long-prismatic and acicular crystals, as dendritic aggregates, and as beautiful "crests" of parallel crystals to 3 cm.

Barite BaSO^sub 4^

Barite is rare at Trepca (BariC, 1948; Zebec, 1974). It forms tabular, white to pale blue crystals, in some cases transparent, to 7 cm on edge, and aggregates of smaller crystals.

Boulangerite Pb^sub 5^Sb^sub 4^S^sub 11^

Boulangerite is found at Trepca as fibrous and very dun acicular gray crystals entangled in downy masses informally called "plumosite." It is generally implanted on rhodochrosite aggregates, witiiin géodes made of rhodochrosite and outer minerals, on galena and pyrite, and frequently as microscopic inclusions in calcite which color the calcite gray or dark blue. The crystals, reaching 30 cm long, have a bright metallic luster when freshly collected, but after a few years the specimens alter to much less attractive, dark gray, velvety-looking masses.

Bournonlte PbCuSbS^sub 3^

Bournonite crystals are very rare at Trepca. They are eidier tabular single crystals or multiple twins of die cogwheel habit to 1 × 1 cm, implanted on galena and pyrite and associated with quartz and carbonates. They are never implanted on sphalerite.

Calcite CaCO^sub 3^

Among the carbonates, calcite is the most abundant at Trepca. It formed as a result of die dissolution of the hosting limestones by volcanic explosions accompanied by a pervasive plume of hot water under pressure which created hydraulic brecciation throughout the deposit. Most commonly calcite forms tightly intergrown coatings of flat rhombohedrons, in many cases twinned, covering vast surfaces of sulfides (sphalerite, galena, pyrrhotite, pyrite) which are dius nearly totally hidden. Some magnificent specimens of sphalerite and pyrrhotite offered for sale at the mineral shows are the result of miners' having dissolved the calcite coatings away with dilute acid. Individual calcite crystals average 1 cm but some reach 7 cm on edge. Most are white, but some are pale yellow to orange because of die alteration of nearby pyrrhotite. Some rare crystals are transparent; others are blue, dark blue, gray or nearly black because of abundant fine inclusions of bournonite or boulangerite.

Chalcopyrite CuFeS^sub 2^

Beautiful crystals of chalcopyrite are radier rare in the deposit despite the production of 2,000 tonnes/year of copper concentrates at Trepca (copper in the ore is contained in chalcopyrite, pyrrhotite, tetrahedrite, tennantite, bournonite, borniteandenargite). Sphenoidal chalcopyrite crystals reach 1 cm on edge.

ChUdrenite Fe^sup 2+^Al(PO^sub 4^)(OH)^sub 2^-H2O

Childrenite was identified from the lowest horizons of Trepca in 1983, but this discovery was published much later, when specimens started to appear at the mineral shows (Zori, 1991; Bermanec eia/. , 1995). The mineral (accompanied by crandallite, its alteration product) forms free-standing, doubly terminated crystals to 1 cm, in aggregates associated with manganese and iron carbonates (siderite, ankerite, rhodocbrosite) or quartz. The childrenite is pale yellow, with zones of white in die cores of crystals and with transparent honey-brown areas at the corners. The specimens with childrenite often contain tiny vivianite crystals. The occurrence of inclusions of boulangerite in childrenite suggests diat die latter was formed under low-temperature hydrodiermal conditions.

Cosallte Pb^sub 2^Bi^sub 2^S^sub 5^

Cosalite crystals from Trepca are rare but very beautiful. In the first discovery (Terzic et ai, 1974, 1975), lustrous, steel-gray to lead-gray acicular cosalite crystals 1.5 to 2 cm long and about 1 mm thick were found in the 8 × 10-cm central void of a 10 × 15 × 20-cm mass of pyrrhotite, pyrite and marcasi te coated by calcite and galena. The galena closely associated with cosalite in this mass has an unusual habit, occurring as elongated, needle-like, isolated crystals, while cosalite appears as much thinner, hairlike crystals.

Dolomite CaMg(CO^sub 3^)^sub 2^

Dolomite specimens from Trepca show beautiful pinkish rhombohedral crystals exceptionally reaching 16 cm on edge and weighing several kilograms, associated widi long-prismatic quartz crystals. The Trepca museum exhibits many large and fine dolomite specimens, one of which is recorded as exceptional in die inventory of Guillemin and Mantienne (1989). In 1974, a dealer from Geneva displayed a very beautiful 25 × 30-cm specimen to one of die authors (JF) while tilis author was working widi a colleague to expedite an exchange widi a famous museum in Paris. In this specimen, a perfect, pale pink rhombohedral crystal of dolomite measuring 5 cm on edge hangs delicately, secured by several acicular, transparent quartz crystals 4 cm long, within a cavity lined by black sphalerite crystals to 3 cm on edge. The dealer whispered mat the Tropca Kombinat had been on me verge of giving this magnificent piece to President Tito, but when die President's scheduled visit to Trepca was cancelled die dealer himself secured die specimen.

Galena PbS

Galena occurs at Trepca as cubic, octahedral, cuboctahedral and cubo-dodecabedral crystals to 7 cm on edge, many of diem highly lustrous. Some of the crystals have corroded or melted-looking faces. Hillock-shaped features on the faces may reveal helical growth. Spinel-law twinned galena crystals are fairly common.

Dvalte CaFe^sup 3+^(Fe^sup 2+^)^sub 2^O(Si^sub 2^O^sub 7^)(OH)

On me Internet, a German dealer recently offered an ilvaite aggregate reportedly from Trepca; it measures 8 × 8 × 9 cm and shows dark brownish green, striated crystals to 4 cm on edge.

Jamesonite Pb^sub 4^FeSb^sub 6^S^sub 14^

Jamesonite is rare at Trepca. Guillemin and Mantienile (1989) describe a specimen in die mine museum showing jamesonite crystals to 4 cm long and 1.5 cm in diameter. Many collectors believe diat a part of me "plumosite" of Trepca is jamesonite, but (to our knowledge) all the mineralogical analyses done on plumosite from Trepca have identified boulangerite and never jamesonite.

Kutnohorite Ca(Mn^sup 2+^,Mg,Fe^sup 2+^)(CO^sub 3^)^sub 2^

A 3 × 3 × 5 -cm specimen from an old collection, labeled as having come from Trepca, was recently sold to us by a French collector as kutnohorite. The specimen displays compact, radial aggregates of pale pink fibrous crystals; me aggregates, reaching 2 cm long and 5 mm thick, are hexagonal in cross-section. Inspection with a binocular microscope reveals that the faces of the minute rhombohedral crystals composing the fibers are curved, and die crystals regularly offset, such diat die edges of me compound prisms tend to form helical lines. Analyses done in the BRGM lab by X-ray diffractometry, electronic scanning microscopy and X-ray spectrometry show that this specimen consists of varying ankerite-kutnohoritedolomite phases: some areas are a Ca-rich rhodochrosite, others are Fe-rich kutnohorite, Mn-rich ankerite, or Mg-dominant phases of either species. From mese results one may at least conclude diat the occurrence of kutnohorite at Trepca is highly probable.

Ludlamite Fe^sub 3^(PO^sub 4^)2-4H^sub 2^O

Ludlamite is apple-green, much paler than vivianite and much rarer (Baric, 1953, 1954). It forms crystals up to 3 cm on edge. Tabular crystals with dominant 001 are up to 8 mm.

Pyrite FeS^sub 2^

Pyrite is not one of the most spectacular sulfides of Trepca, although it is widespread, generally in groups of cubic crystals with individuals 5 mm on edge (exceptionally to 5 cm on edge), or in beautiful globular aggregates. The surfaces of the pyrite crystals are commonly iridescent, showing red, orange, blue, green and violet hues. Pyrite is, with marcasite, one of the sulfides which most commonly replace pyrrhotite in the pseudomorphs for which the locality is so famous.

Pyrrhotite Fe^sub 1-x^S

Trepca has produced remarkable specimens of pyrrhotite, with sharp hexagonal-tabular crystals to 16 cm across, very commonly in parallel aggregates. The faces of the crystals may be clean and lustrous but more often they show coverings or sprinklings of tiny crystals of calcite, dolomite, arsenopyrite, galena or other species, in some cases epitactically oriented. The abundance of pyrrhotite is one of the indications of the very high temperature of formation of the Trepca deposit. Këpuska (1998) identified up to four generations of pyrrhotite crystallization (and three of sphalerite, arsenopyrite, galena, pyrite and chalcopyrite).

Very commonly pyrrhotite has been replaced pseudomorpbically by pyrite (the largest known crystal of pyrite pseudomorphous after pyrrhotite is 30 cm across!) and/or by marcasite. Rare specimens of galena pseudomorphous after pyrrhotite show beautiful, lustrous tabular crystals to 2 cm thick, grown tightly together in parallel aggregates to several centimeters across. Unfortunately, some unstable pyrrhotite specimens have altered by exposure to humidity into a powder of sulfates after a dozen or so years of storage. Another consequence of the pseudomorpbic replacement of pyrrhotite by other minerals is an increase of volume which makes cracks appear in various other sulfides which have grown on the surfaces of specimens; for instance, many of the sphalerite or galena crystals larger than 5 cm are crosscut by open fissures up to 6 mm which rise from the interiors of the specimens.

Quartz SiO^sub 2^

Crystals of white and opaque to colorless and transparent quartz are common, mostly as tiny needles 5 mm long and 1 mm thick. sometimes as prisms of 1 to 5 cm long with a tapered, club-shaped habit, and in some rarer cases sceptered. Thick prismatic crystals rarely exceed about 15 cm long. Wonderful micromount-size specimens are composed of orange-brown, pearl-like spheres of siderite or ankerite seemingly hung like fruits on, or scattered among, acicular crystals of quartz. Very rarely, Japan-law twins composed of two orthogonal prisms each 2.5 cm long have been found (Baric 1977).

Rhodochrosite MnCO^sub 3^

Rhodochrosite occurs at Trepca as coatings with surfaces composed of crystals between 1 and 3 cm on edge; as stalactites; and more rarely as isolated rhombohedral crystals less than 1 cm on edge. The rhodochrosite ranges in color from creamy white to pale pink when the specimen is fresh, but it can oxidize to a pale gray or dirty brown after a few years of exposure. For diat reason, collectors should be cautious when buying a specimen on die basis of an old photo on the Internet.

Siderite FeCO^sub 3^

A Mn-rich siderite (locally called "oligonite") is typical of die Trepca deposit. Stalactites to 1 meter long and 25 cm in diameter have been found. Siderite, despite being widespread, is not spectacular in Trepca, Ae crystals being mostly pink-brown flattened rhombs less tiian a few millimeters on edge, widi curved faces, sometimes in spherulitic aggregates and crusts. Bario (1977) described amazing pseudo-octahedric crystals and rhombs, 1 mm on edge, on quartz needles from die Riesinger collection.

Sphalerite ZnS

Sphalerite from Trepia is black, being very rich in iron; it is found most commonly as octahedral crystals (actually composed of two tetrahedrons in equal development) and spinel-law twins with striated, highly lustrous faces. The crystals have an average size between 2 and 3 cm, but some reach 7 cm and exceptionally 10 cm. Epitactic orientation with pyrrhotite, chalcopyrite or pyrite is frequent (Zebec, 1976, 1977). Calcite, as large, well-developed crystals, is an abundant association. Sphalerite is sometimes associated with small (5 mm), isolated crystals of chalcopyrite, in many cases epitactic on sphalerite. A recent study by Slovenian and German scientists (Srot et ai, 2003) showed that the twin planes (111) of sphalerite are depleted in S and enriched in O, Mn, Fe and Cu; an excess in copper generates the formation of minute chalcopyrite crystals along this plane.

Tetrahedrite Cu^sub 6^Cu^sub 4^(Fe,Zn)^sub 2^(Sb,As)^sub 4^S^sub 13^

Beautiful specimens of tetrahedrite are rare in the deposit. Generally, the crystals protrude from a 1 cm-thick coating of calcite and quartz, and only some parts of their characteristic edges, up to 2 cm long, are visible.

Vlvianite Fe^sup 2+^^sub 3^(P0^sub 4^)^sub 2^.8H^sub 2^O

Vivianite, one of the most famous TrepCa minerals, forms beautiful specimens (Bario, 1965). Its thick-prismatic crystals are up to 10 cm long and 2 cm thick and are relatively stable. They display a very beautiful deep green color and transparency. This iron phosphate has formed as a result of the Trepca deposit's very high iron content (31.5%). The vivianite crystals, averaging 1 cm long, commonly rest on pyrrhotite or pyrite, and in some cases on quartz or carbonates. Previous authors thought the mineral was restricted to the upper third of the mine, but new specimens were found last year on the lowest levels.

Rare Metals

In addition to die 60+ mineral species already identified there, die Tropèa deposit seems likely to yield still more, since mineralization occurred under a wide range of conditions: pyrometasomatic, catathermal, mesothermal, ephhermal and supergene. Abundant iron and sulfur in die ore-bearing solutions gave rise to abundant pyrrhotite, and the many other available metals gave rise to numerous odier sulfides and sulfosalts. However, die most surprising aspect of TrcpCa mineralogy so far is the presence of secondary iron phosphates such as vivianite, ludlamite and chUdrenite. Since rare metals such as indium, germanium, gallium, thallium and selenium become increasingly abundant as investigation proceeds downdip in the orebody, discoveries of additional species during the coming years seem highly likely.

No data concerning occurrences of these rare metals at Tropca had been published before the work of Kepuska (1998), who collected 128 ore samples at various depths in the deposit and, through electron probe microanalysis and atomic absorption spectrometry, assayed the rare metals present in sphalerite, galena, pyrrhotite and pyrite crystals, with the results shown in Table 2.

Unfortunately, data are still lacking concerning germanium in sphalerite - the mineral which is the usual Ge and Ga-bearer in world zinc deposits. For Ge, besides the maximum 180 ppm in pyrite, Këpuska reported 3 ppm in rhodochrosite, 1 ppm in dolomite and 2 ppm in skarn (the latter three figures do not seem convincing).

Concerning indium, the figures that have been published do not appear to be representative of the orebody (UNMIK/rrepca Ch. Carrón Brown's personal communication of a table by Sh. Kelmendi, 2006, comparing two analyses done by the Swiss SGS laboratory). According to this table, one rather old (1997?) sample of Stari Trg ore concentrate containing 46.8 % Zn yielded 20 ppm indium. This figure is low as compared to the 200 ppm indium found in one old sample of Novo Brdo (Kishnica) ore concentrate which was rather rich in tin (1 10 ppm Sn). Within the Stari Trg concentrate sample, Sn, Tl, Te and Se were below the detection limit. Elevated indium grades might well be expected during the next few years of ore exploitation, in light of the significant increase of indium grades downdip as shown by the analyses of Këpuska (1998).

Further analyses by the authors are currently in progress in the BRGM laboratories, and the results will be published as soon as possible.

THE PRESENT SITUATION AT TREPCA

Mme Workings

Starting from the medieval open pit at the 935-meter elevation mark, underground mining has proceeded by the cut-and-fill method. Access to the stopes was previously provided by a few adits at the top of the mine (at heights of 865, 830, 795 and 760 meters), but then, in order to follow the orebody downdip, a first shaft was dug at 6 10 meters to give access to other levels. A de watering adit called the "Prvi Tunnel," running southwest for 2.2 km, begins at the 605-meter mark. Shafts dug later as the mine developed include the "blind shaft," running down to an elevation of 15 meters above sea level, the "new shaft," and two accessory shafts for ventilation and rescue. The main shaft has a circular cross-section and is 7 meters in diameter, including four separate compartments respectively for the 5-ton skip, the 2-fioor lift for workers or materials, the ladders and the logistical pipes. The deepest level of mining attained to date is the 11th level, at 15 meters above sea level. Drill-boles have proven that the mineralization extends still further downdip. The total vertical extent of the mine is presently 800 meters and the total elongation of the ore deposit along the strike is over 1,000 meters. At each level, the mining stopes are elongated horizontally on both sides of the volcanic pipe intersection, along the two sides of the antiform, over a total length of about 1,400 meters toward the northeast and 600 meters to the south. Each stope is about 70 meters wide and 100 meters long.

Production Figures

The total production of Trepca from 1931 to 1998 is estimated at 34,350,000 tonnes of mine-run ore having grades of 6% Pb, 4% Zn, 75 grams/tonne Ag and 102 grams/tonne Bi. The ore was beneficiated in the Prvi Tunnel (Tuneli Pare) concentrator (flotation), whose capacity was 760,000 tonnes/year. The lead concentrates were brought to the lead smelter of Zvecan (capacity 80,000 tpy), and the zinc concentrates were brought to die zinc electrolytic smelter of Mitrovica (capacity 50,000 tpy). There was also a unit for die production of fertilizers using die sulfuric acid byproduct of me hydrometallurgy, and lines of battery production and battery recycling.

The total metal tonnage produced from 1931 to 1998 was 2,066,000 tonnes lead, 1,371,000 tonnes zinc, 2,569 tonnes silver and 4,1 15 tonnes bismutii. Gold production is estimated at 8.7 tonnes from 1950 to 1985, i.e. an average of 250 kg per year. Cadmium production is estimated at 1,655 tonnes from 1968 to 1987. Traces of germanium, gallium, indium, selenium, diallium and tellurium in me mine-run ore have also been reported, and diese were extracted at die smelters.

Future Mining

Resumption of full-scale mining at Trepca in the near future is now expected. First however, private investors must be attracted, and mining techniques must be improved so as to prevent any new environmental pollution. Implementing die present program for updating die plants will be expensive: a cost of 15 to 30 million U.S. dollars for die whole industrial complex has been suggested. For die time being, die smelters have not been reactivated. Since September 2005 die mine has only produced zinc, lead and copper concentrates at an average rate of 5,000 tonnes/month, and diese concentrates have been sold to traders. The silver, gold, bismuth, cadmium, indium, germanium and gallium of die various ore concentrates are extracted at die foreign smelters which buy and process the Trepca concentrates (togedier widi batches from other deposits).

Calculations published on die Internet (TTT Kosovo Consortium LTD, 2001) suggest tiiat enough ore reserves remain at deptii in die Trepca mine to justify die effort and cost of resuming full-scale mining. The myUNMK 2001 report concluded that about 29,000,000 tonnes of mine-run ore at grades varying (according to die panels considered) from 3.40 to 3.45% Pb, 2.23 to 2.36% Zn and 74 to 81 grams/tonne Ag, i.e. around 999,000 tonnes Pb, 670,000 tonnes Zn and 2,200 tonnes Ag, could be produced. This potential would justify several more years of mining, if die operating costs and the prices on the metals market permit it. At current market prices, copper produced in Trepca at a 2,000 tonnes/year would be a bonus.

Politically and socially, reawakening die sleeping Trepca giant" is a worthy goal. Full-scale mining would provide many new jobs and thus revitalize diis part of Kosovo economically, returning pride and hope again to the people. And mineral collectors, meanwhile, would have tiieir own very good reasons to welcome any revival of major mining at Trepca.

However, if selective mining metiiods go on being privileged, die consequence for mineralogy will be that die lowest grade orebodies, diose hosting unworkably large masses of Mn-rich siderite ore and drusy carbonate karst fillings, will not be mined. In tiiat case, die only crystals unearthed by new mining will be sphalerite, pyrrhotite, pyrite and minor amounts of galena and jamesonite- die typical components of die massive sulfide ore bodies. Discoveries of die wonderful geodes made of various mixed carbonates and sulfides will cease, and that would be a great loss for science, for museums and for collectors.

The Mineral Museum

When bad luck seemed to have overtaken die Trepca museum, a few mineralogists and friends of Trepca in France volunteered to bring help, at tiieir own cost to die Trepca mine directorate and to die curator of die Trepca museum. The aim of an independent team tiiat visited Trepca was to assess die situation and, witii the consent of die authorities in Kosovo, to find ways to advise and assist die museum in recovering its financial resources and its worldwide influence, and in recovering whichever of its mineral specimens had been stolen (happily, it turned out tiiat none had been stolen). From September 1 1 to September 1 8, 2005, an exploratory team made the journey to Kosovo. On me team were Joël Balazuc, Carole Frima, Pierre-Christian Guiollard, Benjamin Larderei, Skender Plakolli, Michel Schwab, Jérôme Schwab, Jocelyn Vendei and Jean Feraud. This team received a very warm welcome and efficient help from authorities in Kosovo. Great thanks are extended to me Trepca/ UNMIK Managers in the Kosovo Trust Agency, to die directors of die Trepca mine, and to all die engineers and scientists who made the visit so pleasant and so professional.

The team observed mat me mineralogical collections are intact and in a ramer good state of preservation. Clearly me Trepca mineral museum is a heritage of national importance for Kosovo: me collection is invaluable, and of an interest far beyond die merely local or regional. Many specimens are of international importance, i.e. "world-class," and die team judged diat me entire museum deserves to be ranked among the top 100 mineralogical museums worldwide.

Unfortunately, die team could not report such good news about die condition of die building itself. The roof and die walls are no longer waterproof, the paint on various walls and on die ceilings is seriously damaged, and the museum lacks a heating system, and even a fire-prevention system. In the collection, many iron sulfide specimens have disintegrated as a result of die high humidity.

Encouraged by die warmdi and supportiveness of all die Kosovan audiorities, engineers and scientists whom diey met, die team members wrote a report (in French, with an English summary: Feraud et ai., 2005) offering the following:

(1) Ideas to improve the building, including its roof; to install an electrical heating system (or to shift the building to another place nearby); and to repaint all surfaces.

(2) Ideas to improve the way in which die collections are exhibited; to clean die specimens; to inventory and catalog die collection; to improve die exhibit areas by introducing teaching tools in order to increase the interest of visitors (e.g. put some educational posters on die walls, select the most interesting specimens to display and put many less interesting ones into storage, collect and display old machines and documents concerning die mine and me processing plants and smelters).

(3) Ideas about die legal status of die museum. The mine, once run by a state-owned company, was expected to be purchased by a private investor soon; mus the museum would be controlled by a private company. But a museum can receive money from public entities - from die EU and from UNESCX) - only if it is state-owned. Therefore it is urgent diat UNMIK-Trepca help to transfer die museum to die Ministry of Culture or some public institution instead of allowing it to be sold to a private investor. Thanks to our efforts to sensitize die audiorities to diese matters, die transfer process is now underway. Nonetheless, we strongly suggest diat die mine should retain its place in the museum directorate and diat me government of Kosovo, by creating tax incentives, should promote patronage.

(4) Ideas to enhance die reputation of die museum (widiout huge expenditure) so mat Trepca becomes a place of national and even international importance in the mineral world, and perhaps also a recreational resort It is suggested mat an Internet website be created to publicize Trepca, including its possibilities for sustainable development The Trepca museum deserves to play a great role in teaching young generations of Kosovans about minerals, mining and die environmental heritage, and in encouraging die interest of youdi in die scientific and technological professions.

This report has been widely distributed, as paper copies and as e-mails with attached .pdf-files (together widi personalized cover letters), to national and international institutions and experts in positions to help die museum. Recipients include die Kosovan President me parliament and concerned ministers and administrators in Kosovo, die European Union, die United Nations, UNESCO, die European Bank for Reconstruction and Development The World Bank, The Council of Europe, me great museums, etc. Additional copies are available upon request.

In another step following its report, the team established a "supporting committee," the mission of which is to pursue the efforts and in particular to launch communications on behalf of the museum. This committee is made up of the team members who went to Kosovo, but it is open also to any institute and individuals of good will who would participate in the committee's activities or who simply wish to "join the crew."

In order to attract French and international grants for the museum, a Trepca exhibition was presented by the committee, together with Euromineral, at Sainte-Marie-aux-Mines, France, on June 22-25, 2006. The exhibition benefited from the support of several organizations and scientists. Including Michel Schwab and his MINERAL Concepts Sari, the BRGM, P-C. Guiollard Editions, the GEOPOLIS association, and Hacene Bouafia of GRAFIK'Expo Sari (for the design of the poster). The General Director of Trepca (Nazmi Mikullovci), the Director of the mine (Myftar Hyseni), and the three authors of this article were on hand to welcome visitors and to explain the geology and mineralogy of Trepca and the current situation there. Contributions to a fund to aid the museum were solicited, and the 1,000 Euros collected were used to purchase two binocular microscopes for the museum.

Another exhibition was presented at the München Mineralientage of November 2006 in Germany. Other exhibitions are planned in Dortmund and in Hamburg. Also, the supporting committee began taking subscriptions which were coupled with a contest, the prizes of which were spare mineral specimens provided by the mine and/or the museum.

The Trepca museum is a national patrimony for Kosovo, and its rejuvenation should be given higher priority than heretofore, even in view of the fact that postwar Kosovo has innumerable problems yet to be solved. To make an inquiry, to offer help, or just to join the crew, please contact musee-trepca@hotmail.fr or the senior author.

ACKNOWLEDGMENTS

The authors thank the Trepca directorate and particularly Nazmi Mikullovci, Charles Canon Brown, Myftar Hyseni, Beqir Maliqi, Shyqri Kelmendi (Shyqa) and Skender Plakolli. For their support and advice, great thanks are extended to Jack Testard, Yves Deschampe and Christian Hocquard of the BRGM. Among collectors and friends, we are indebted to Werner Lieber, Frank Wierich, Christiane David, Franz Huber, Achim Larghi, Dona Patz, Joel Balazuc, Marc Binon, Jean-Jacques Breuer, Benjamin Larderei, Alain Marteaud, Pierre Rostan, Michel Schwab, Patrick Vadala, Jocelyn Vendei and others. The photos and mineralogical specimens illustrated here belong to J. Féraud, except for those kindly provided by Dr. Werner Lieber.

Source: Mineralogical Record

 

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