Mechanical ore processing at the Nerchinsky Zavod plants in the 19 century

Abstract

The article covers ore processing for the production of silver and lead in the Nerchinsky Mountain District in the 19 century, which was first introduced there in the difficult local conditions, including poor ores with a significant diversity of properties, long distances to the Russian and European metallurgy centers, and the historically established practice of immediate ore mining without preliminary exploration of the entire deposit. This practice naturally resulted in persistently unprofitable operation of the Nerchinsky Zavod plants after 1791. The operations were only supported for the sake of supplying lead to the silver mills of Altai. In fact, the profits of the Altai mills would cover the losses of the Nerchinsky Zavod plants. Since 1821, administrative measures had been implemented at the Nerchinsky Zavod plants to ensure more thorough manual analysis and sorting of the ores; however, in 1826, conventional washing workbenches were introduced for the washing of ore fines without differentiation of any ore properties. In 1830 to 1849, the Ministry of Finance had been making significant efforts to introduce mechanical ore processing. Since 1830, ore pounding had been used, with the separation of sludge in gold washers. This method was justly criticized a few years later. The poor separation results were due to the impurities in the clay and to the application of the same separation method for different ores. Following his trip to the mountainous districts of Germany and Hungary, mining engineer Kovrigin opted for the use the Oberharz processing method in view of the similarity of the properties of the ores mined. In 1840–1853, the Kovrigin’s program was implemented for the processing of Nerchinsky District ores to produce silver and lead. As a result, 318 processing devices were then operated at 32 plants (compare with 93 devices at eight plants in 1830–1835). The article contains comprehensive statistics on the results of ore processing at the Nerchinsky Zavod plants.