THE FOUNDRY
RAVINE
The ore mined in the mine contained about 1 gram of gold per tonne. The gold was in the form of microscopic granules, occurring in the crystal lattice of gold-bearing minerals; loellingite, arsenopyrite, pyrite and pyrrhotite. Extracting the gold required many metallurgical operations. First, so called "crude stone" was smelted out of the ore.
Between 1530 and 1560 in the foundries of Złoty Stok 60 tonnes of ore, mined in the nearby mines, were processing every day. About 500 grams of gold were extracted out of the ore. In the furnaces 60 cubic metres of charcoal were burnt.
The ore mined in the mine contained about 1 gram of gold per tonne. The gold was in the form of microscopic granules, occurring in the crystal lattice of gold-bearing minerals; loellingite, arsenopyrite, pyrite and pyrrhotite. Extracting the gold required many metallurgical operations. First, so called "crude stone" was smelted out of the ore.
 For that charcoal was used. Smelted ore was poured into the clarifier that was in front of the furnace. Heavy alloy of minerals gathered at the bottom of the clarifier. The congealed slag was taken out of the surface of the alloy with an iron hook and was thrown onto the heaps. |
 The "crude stone" was roasted three times. It was put on the pile of wooden rods and fired. During the process of roasting sulphur and arsenic were burnt, and molecules of gold occurring in their crystal lattice were released. |
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The
"crude stone", now roasted, was again smelted in the
furnace then some lead was added. The lead helped to rinse out
the molecules of gold.
The alloy was poured into the clarifier and the slag, floating in the liquid lead, was collected. Finally, the slag was thrown onto the heaps. And from the lead, containing gold, special "loaves" were cast in the forms. The "loaves" of lead were laid on the plate under the dome of the furnace and heated with beech rods, as shown in the photo. The lead melted and oxidized forming litharge (PbO). The fused litharge penetrated the plate of the furnace and settled on its dome. Finally, on the surface of the litharge a lump of "crude gold" was left. The lump was given to the mint. |
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The heaps of black
slag, occurring along the ravine, are the waste of metallurgical
processes in which the gold was extracted from the gold bearing
ore. The biggest number of foundries worked in the ravine in the
16th century.
  zoomThe plan of the slag heaps and the underground excavations of the mine. |
Between 1530 and 1560 in the foundries of Złoty Stok 60 tonnes of ore, mined in the nearby mines, were processing every day. About 500 grams of gold were extracted out of the ore. In the furnaces 60 cubic metres of charcoal were burnt.
