Alteration zones extracted by remote sensing provide important guidance for early stage exploration of hydrothermal deposits, however, many of them are not mineralized. Therefore, it is desirable to develop a method for determining alteration zones with mineralization based on the satellite data. In this study, we attempted to detect oxidized copper minerals using data obtained from a commercial satellite Worldview-2 that can observe photons from the visible to the nearinfrared region (VNIR). The analysis was tested at Chalhuane District, Arequipa Province, Republic of Peru, where the mineralization of the porphyry copper deposit is already known. As a result of trying to detect the oxidized copper minerals distribution area by ratio operation processing (second derivative of Band 3), the high Cu anomaly area (>1,000 ppm) coincides with the second derivative value distribution area. The lower detection limit of copper oxide is estimated to be approximately 1,000 ppm of copper. Even small amounts of oxidized copper minerals can be detected because (1) the dynamic range of the satellite data was so large that even slight changes in the spectra could be observed, (2) copper oxide generally forms a thin film, hence, the ratio of the surface coverage of the oxidized copper minerals to their weight is large and (3) the wavelength that was set in the optical sensor was suitable for detecting the oxidized copper minerals. As for iron oxide minerals, the second derivative of Band 6 distribution area, limited within the alteration zone by the previous survey, coincides with the area in which disseminated pyrite is observed. In conclusion, it was possible to specify the alteration zones with mineralization by combining the conventional method of using short-wavelength infrared radiation with the proposed method. Furthermore, by using a hyperspectral sensor of HISUI that is scheduled to be launched in the near future, it is expected to detect mineralization with higher precision.

The Hishikari epithermal gold-silver deposit consists of three deposits, the Honko deposit, the Sanjin and the Yamada deposit. Some of veins in the Honko and the Sanjin deposits terminate at the surface of unconformity between sedimentary basement rocks of the Cretaceous Shimanto Supergroup and volcanic rocks of Quaternary age, named the Hishikari lower andesites, even though the others continue from the basement to the volcanic rocks. In this paper, we discuss the relationship between quartz veins and the surface of unconformity in the Honko and the Sanjin deposits based on the underground development data from -20ML to 110ML. The veins not controlled by the surface of unconformity are widely distributed in the Honko and the Sanjin deposit. They were formed by normal and strike-slip faulting. The stress magnitude of the fault activities related to the formation of these veins would have been small because the fault displacement is relatively small. Most of quartz veins controlled by the surface of unconformity are distributed in the Hosen and Zuisen vein systems and the Sanjin deposit. The strongly argillized Hishikari lower andesites overlying the Shimanto Supergroup formed selectively in the Honko and the Sanjin deposits and the argillized zone seems to have a great effect on the formation of these veins. The strongly argillized layers might have been formed before around 0.9 Ma prior to the occurrences of quartz veins controlled by the surface of unconformity.

Tizapa mine is a polymetallic volcanogenic massive sulfide ore deposit located in state of Mexico, Mexico. The deposit consists of three ore bodies, East, Central and West. The mineral resource of the deposit is determined by data of surface/underground drillings and channel samplings. Quality assurance of sampling is performed by standard samples (ore sample with known values, blank and duplication) inserted every 10 samples. It's carried out the verification of blank sample by statistical tests to assure the results of sample analysis. The values of lead, zinc, copper and iron in the blank sample were set statistically the tolerances, so the blank sample attests the validity of sampling. Underground drillings and drifting were carried out in 2018 to explore the extension of West ore body. The samples from drilling and drifting are processed and assayed with verified blank samples. As a result of exploration, the mineral resource was obtained 76,906 t.

Copper Mountain Mine (BC) Ltd. (CMM), which is 75% owned by Copper Mountain Mining Corporation (CMMC) and 25% owned by Mitsubishi Materials Corporation (MMC), is located 20 km south of Princeton, British Columbia, Canada.

CMM has produced copper concentrate since the mine reopened in 2011. Since 2017, a Geo-Met program has been carried out as a cooperative project by geologists and metallurgists of MMC and CMMC. The objective of this project was to understand the variance of flotation performance for various ore types throughout active mining areas and to map out the CMM mine site on a copper recovery basis to improve the accuracy of the copper production forecast.

It was revealed that copper recoveries were correlated with grain size of copper minerals, especially chalcopyrite, which is the primary copper mineral of the deposit. At first, blast-hole cuttings were visually observed in four active mining areas (Pit2 South, Pit2 West, Pit3 Stage3, Oriole Pit). The cuttings were classified based on the grain size of chalcopyrite or bornite, such as “(Very fine (<0.1 mm)”, “Fine (0.1 mm - 1 mm)”, “Medium (1 mm - 3 mm)” and “Coarse (>3 mm)” in order to understand the distribution of ore types throughout the area.

In addition, diamond drill-hole cores were re-logged with copper mineral grain size information to understand the ore type distribution at depth and in future mining areas. The observations of copper mineral grain size were quite consistent from the surface and at depth within the same area. Both observations of blast-hole cuttings and historical drill-hole cores were compiled and modelled in a mining software, Surpac. A laboratory flotation campaign for composite mining packets was conducted to understand the copper recovery behavior in the rougher flotation for various type of ores. As a result of studies from geological and metallurgical observations and test works, four copper recovery domains were created. These four recovery domains are predominantly classified by copper minerals grain size observations. They are defined as “Very fine to Fine”, “Fine”, “Fine to Medium” and “Medium to Coarse”.

The estimated copper recovery with the newly established recovery domains for the period of July 2016 to July 2017 fell into line with the actual mill performance. It was concluded that these copper recovery domains would improve the process of forecasting production and contribute for more accurate production budgeting.

As a result of this project, the copper recovery domains have been established and introduced into a block model and utilized for the actual budgeting and mine planning process since the first campaign was completed in 2017.

The 15th Chilean geological congress was held at Concepción in November 18th to 23rd, 2018. A total of 1171 scientific presentations were made and more than 1300 persons attended in this congress. A short report on the congress, particularly on economic geology session, is given here for Resource Geology members. In the economic geology session recent progresses regarding porphyry and IOCG-type deposits, microanalytical studies on some ore minerals, and development of Chilean geothermal projects were particularly introduced.