CHARACTERIZATION OF TOGURACHI WASTE ROCK AND TAILINGS PT. NUSA HALMAHERA MINERALS AND STUDY OF ITS PROCESSING POSSIBILITY BY HEAP LEACHING
PT. Nusa Halmahera Minerals (PT. NHM) is conducting a study to process waste materials that are estimated to still contain gold and silver that can be extracted. The waste materials are waste rock from the Togurachi Mine and processing plant tailings. With relatively low gold and silver contents in...
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| Format: | Final Project |
| Language: | Indonesia |
| Online Access: | https://digilib.itb.ac.id/gdl/view/46757 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | PT. Nusa Halmahera Minerals (PT. NHM) is conducting a study to process waste materials that are estimated to still contain gold and silver that can be extracted. The waste materials are waste rock from the Togurachi Mine and processing plant tailings. With relatively low gold and silver contents in these two waste materials, the processing options to be studied is the heap leaching technique. In this study, mineralogical and mineragraphy analyses, Au and Cu diagnostic leach, percolation and column leach experiments were performed on waste rock from the Togurachi Mine and tailings PT. NHM to determine the characteristics of the waste materials and to study the effectiveness of gold extraction process from the waste rock and tailings by using heap leach method.
The study began with the preparation of waste rock and tailing samples which were included crushing (only for waste rock), sampling, and sieving followed by characterization of dominant minerals in the waste rock and tailings with X-Ray Diffraction (XRD), chemical composition analysis with X-Ray Fluorescence (XRF), head grade analysis with fire assay and Atomic Absorption Spectrophotometer (AAS), and mineragraphic analysis of polished section samples. Gold and Copper diagnostic leach tests were carried out to determine the distribution and association of gold and copper in various minerals in the waste rock and tailings. Percolation testing was conducted to determine the quality of agglomerates prior to be uses in the column leach tests by adopting the Kappes Percolation Test method. Column leach tests were carried out in a flexy glass column for 44 days for the crushed waste rock and the tailings : waste mixture of 1:1 (w/w) and for 60 days for the agglomerated waste rock and the tailings : waste mixture of 1:2 (w/w). Measurement of dissolved Au, Ag, and Cu concentrations as a function of time was carried out with AAS.
The results of XRD, XRF, and mineragraphic analyses show that Togurachi waste rock and processing plant tailings are dominated by silicate minerals with low clay content. Gold diagnostic leach results on waste rock and tailing show that free gold is the most dominant gold among the gold present in the waste rock and tailing. The results of percolation testing showed that agglomeration and blending of tailing with waste rock were required in order the leaching solution can flow smoothly through the heap feed in the column. The column leach test results showed that the highest Au recovery of 66.89% was obtained from agglomerated waste rock with Ag recovery of 89.16%, and co-dissolved Cu of 18.89%. Overall test results indicate that Togurachi waste rock and its mixture with tailing at weight ratios of ? 1: 1 can be extracted by heap leaching.
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