Uralgiproruda Institute, Ekaterinburg, Russia:

P. Yu. Zherebchikov, Category I Engineer, Mining and Geology Sector, mail@ugruda.ru

Frequently, mineral appraisals and quality requirements made decades ago omit modern economic conditions and need refi nement. In view of higher demand for low-grade brucite, Uralgiproruda Institute has completed re-appraisal of Kuldur deposit, including brucite of grades IV and V earlier regarded noncommercial. Brucite is a natural magnesium hydroxide composing most of brucite ores. Application range of brucite is extremely wide. Kuldur deposit contains 5 identified grades of brucite. Grade of brucite is condidioned by contents of useful component MgO and toxic components CaO, SiO₂ and Fe₂O₃. Currently, the mine successfully operates a crushing-and-grading system based on two X-ray radiometric separators SRF4-150 and SRF3-300. This has enabled total elimination of manual grading of brucite, ensured improved quality of brucite and allowed enlargement of production output. First, Uralgiproruda experts visited the mine site and collected source data. Then, the Geology Sector of the Institute prepared the source data for further processing. Three-dimensional modeling of the ore body zone and open pit mines used Surpac software, which greatly improved calculation speed and efficiency of analysis of open pit mining scenarios. The technical-and-economic assessment of permanent quality requirements included two mining scenarios:
• Scenario I — extraction of commercial brucite grades (I+III ), including grades IV and V within the open pit mine limits;
• Scenario II — extraction of all proved reserves (grades I–V).
Specialists of the Mining and Geology Department constructed 3D models of open pit mines to make an optimized choice. Based on the outcome of the technical-and-economic assessment, scenario I was selected as the optimal variant to ensure the highest performance and to account for interests of the state and subsoil user. In this manner, the introduction of brucite grades IV and V in mining has increased geological reserves of Kuldur deposit by 42.7%. Uralgiproruda Institute accomplished with success the technical-andeconomic assessment of the deposit and re-appraisal of brucite reserves under the modern economic conditions. The results were the permanent quality requirements and entering brucite grades IV and V in the state register. In view of the re-appraisal of brucite reserves, the Institute updated the mining project documentation for Kuldur deposit. 

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