Development of geometallurgical characterization and comminution testing of the Kittilä gold deposit

• Main Author: Lange, Maja
• Other Authors: Kangas, Lasse, Insinööritieteiden korkeakoulu, Leveinen, Jussi, Aalto-yliopisto, Aalto University
• Format: Master Thesis
• Language: English
• Published: 2019
• Subjects: geometallurgy; comminution; crushing; milling; grindability; Kittilä; Northern Finland
• Online Access: https://aaltodoc.aalto.fi/handle/123456789/41677

Efficient measurements of comminution are important for testing the variability of the ore within the geometallurgical context. An essential part of this work is the investigation of the influence of texture, mineralogy, liberations of minerals and density on the grindability of the rock. Parameters such as the Bond Work Index and the Point Load Index are commonly used to optimize comminution processes. Comminution testing is key to the proper geometallurgical characterization of various deposits. The focus of this study has been to develop geometallurgical characterization and comminution testing, which allows efficient measurement of crushing or grinding indices and their connection with mineralogical parameters. The results from comminution testing were collected and used to determine the crushability and grindability properties of the Kittilä gold deposit (Northern Finland). For this thesis, three tests were conducted – JK Drop Weight impact test, Bond Ball Mill and Point Load Strength test. Furthermore, mineral composition and density measurements have been determined for a detailed analysis of the samples. Statistical analysis was carried out by using IBM SPSS software. The conducted tests are designed to be implemented in early stages for identification of differences in comminution properties leading to detailed geometallurgical characterization of the ore. Later testing and sampling can be done on a bigger scale to obtain efficient and economical circuit design. From the results, it was concluded that there is a strong positive relationship between the grindability and crushability of the ore. It was also confirmed that the mineral composition, hardness of the ore and rock texture influence rock breakage mechanisms. All of the comminution tests, were strongly and positively correlated to each other. The Point Load Test can be used to indicate the ore hardness rather than time-consuming and complicated Bond Ball Mill Test.