Epithermal Gold

(Unless otherwise indicated, all historical drilling, sampling and production data in this section of the website was found in the Metal Mining Agency of Japan database.)

Japan Gold has a total of 13 separate project areas prospective for high-grade epithermal gold mineralization. Ten of the projects are located on the island of Hokkaido, and three of the projects are located on the island of Kyushu. All of the prospecting rights applications covering these projects have been accepted, reserving the ground for Japan Gold and allowing for surface forms of exploration such as mapping, geochemical sampling and geophysics. To date, 23 of the 56 applications over the Ikutahara Project have been granted as Prospecting Rights authorizing the Company to commence more advanced exploration methods, including drilling. Scout drilling has commenced at the Akebono prospect at the Ikutahara Project. Japan Gold has generated other compelling drill targets, focussing on high grade epithermal veins in and around historic mines and workings, and will seek to rapidly progress these targets to the permitting phase so that they can be drill tested in 2018.

Location of the Ten Hokkaido Epithermal Gold Projects: 

Location of the Three Kyushu Epithermal Gold Projects:

 

The Ikutahara Project

Overview

The 19,114 hectare Ikutahara Project is Japan Gold’s most advanced project. It comprises 56 prospecting rights applications, 23 of which have been granted as Prospecting Rights by the Japanese Ministry of Energy, Trade and Industry (METI), authorizing the Company to commence more advanced exploration methods, including drilling. A drilling permit has been granted for the Akebono prospect and scout drilling is has commenced.

The project covers 17 historical gold mines and workings which were discovered and intermittently mined between 1910 to the government imposed closure of gold mines in 1943. Many of the historic workings that were active in the area stopped in ore and never reopened. The project area has seen only minor exploration since that time.

From October to December 2016, six geologists and support teams undertook a nine-week field program at Ikutahara. These results have been compiled to further define targets for additional detailed prospect mapping, surface geochemical and drill testing.

 

The Prospecting Rights

To date, 23 Japan Gold’s 56 prospecting rights applications over the Ikutahara Project have been granted as Prospecting Rights.

The Akebono prospect is covered by the 23 Prospecting Rights. Akebono is one of the 17  historic mines and workings reported within the Ikutahara Project area.

Discovered in 1931, underground exploration at Akebono was carried out between 1938 and 1940, however, no production records were reported prior to government imposed gold mine closures in 1943. In the 1960’s the underground workings were re-entered and sampled and several high-grade samples were reported. Details of these historic assay results were published by the Metal Mining Agency of Japan1, high-grade intervals include 1.2 metres @ 446 g/t gold and 376 g/t silver and 0.65 metres @ 91.5 g/t gold and 4,891 g/t silver.

The surface mapping conducted by the Company during 2016 and 2017 has identified a steeply dipping, northeast trending vein system with widths up to four metres and a strike length of over 770 metres open both to the northeast and southwest.

The initial scout drilling program, of up to six holes totalling up to 1000 metres of diamond drilling, will aim to confirm and extend historic high-grade underground sampling to define the potential for high-grade shoots in the Akebono vein system. The drilling program is expected to continue into late December with results anticipated in February 2018.

Nine other historic mines lie within the granted Prospecting Rights, some of which had prospecting and exploration work programs carried out on them late last year. These include the Saroma, Taiho and Taihoku mines. Detailed mapping and surface sampling has already commenced this season to better define these areas of mineralization for drill targeting.

1 Metal Mining Agency of Japan, March 1990, Geological Survey Report for Fiscal Year 1989, Northern Hokkaido Area B – Metalliferous Deposits Overview.

Other Targets

Detailed surface work will also focus on the other significant targets that lie within the 33 application areas still under review by METI. Targets here include the high-grade Ryuo mine area, the Kitano-o mine reported to have produced 96,450 ounces of gold from gold-bearing eluvium associated with sinter deposits and sub-sinter epithermal veins, and the Ikutahara, Showa and Chitose mine areas.

Ryuo Mine Area: The Ryuo mine was developed on six levels with veins up to 1.6 m wide. Incomplete production records show more than 5,000 ounces of gold produced between 1938-1953, with grades averaging 8.9 g/t gold and 36 g/t silver. The Jinja vein measured 120m x 70m x 1m with an average grade of 13.99 g/t gold and 110 g/t silver, and the Shoei vein measured 200m x 90m x 1m with an average grade of 5.21 g/t gold and 132 g/t silver.

Kitano-o Mine Area: The Kitano-o mine was the district’s first major producer, with an estimated 96,450 ounces of gold mined at an average grade of 5.9 g/t gold between 1924-943 from mining of gold-bearing eluvium associated with sinter deposits and sub-sinter epithermal veins within rhyolitic volcanic rocks. Within the central part of the project area the Kitano-o, Showa and Ikutahara mines represent a unique style of ‘high-level’ gold mineralization. Sinter deposits generally represent the surface expression or outflow of epithermal vein systems developing at depth. The Company will be exploring for such vein zones that may lay at depth beneath these high-level deposits; and depth and strike extensions of the numerous other vein targets.

Ikutahara Project Area – Historical Mines

The Aibetsu Project

The Aibetsu Project comprises 22 accepted applications (7,034 hectares) in northern Hokkaido. Five historic epithermal gold / silver and mercury mines are located within the Aibetsu Project area. The Aibetsu Project area includes the Tokusei mine, which produced 38,580 ounces of gold and 472,620 ounces of silver between 1930-1942¹.

The project area has had only minor exploration since the 1940’s which included mapping, soil sampling, and resistivity surveys by MMAJ over the Tokusei mine area between 1998-2002. This work culminated in five deep diamond drill holes targeted mainly on Tokusei mine extensions. Narrow high-grade gold and silver intercepts in two drill holes targeted beneath a mercury soil anomaly located approximately 500 m northeast of the Tokusei mine workings, included 0.95 m @ 69 g/t gold, 263 g/t silver (13MAHB-1) and 1.15 m @ 12 g/t gold and 7 g/t silver (13MAHB-2) 2, at about 300 m and 450 m below surface respectively. A wider gold intercept of 7.5 m @ 1.92 g/t gold and 11 g/t silver (14MAHB-1) was recorded from drill hole 14MAHB-13 located approximately 500 meters to the southeast of drill hole 13MAHB-1 along a parallel structure.

Within the pre-existing applications, the Company plans to infill and extend southwards, from previous MMAJ mapping and soil geochemical sampling completed over the Tokusei mine area, to define new drill targets. Surveying and clearing of grid-lines to allow access for mapping and soil sampling commenced in mid-May 2017, soil sampling is expected to commence in mid-June 2017. Mapping conducted along some recently cut grid lines has confirmed the presence of silica capping and sinter outcrops on Mt Maruyama above the Tokusei veins, indicating that limited erosion has occurred and that the vein systems are therefore well preserved.

1Watanabe, 1996. Genesis of Vein-hosting Fractures in the Kitami Region, Hokkaido, Japan. Resource Geology, v46(3), pp 151-166, 1996.
2Metal Mining Agency of Japan, Geological Survey Report for Fiscal Year 2002, North Hokkaido Area.
3Metal Mining Agency of Japan, Geological Survey Report for Fiscal Year 2003, North Hokkaido Area.

Figure 1 -Aibetsu Project Area and Simplified Geology

Figure 2 - Aibetsu - Historic Mine and Drill Holes 

 

The Tenryu Project

The Tenryu Project consists of four contiguous prospecting rights applications covering an area of 1,267 hectares and is located three kilometres southeast of Japan Gold’s Aibetsu Project. Little information is available on the Tenryu workings which closed in the early 1940’s, however a cyanide gold extraction plant was located four kilometres downstream of the now collapsed portal which is believed to have processed ore from Tenryu and other workings nearby in the early 1940’s. Tenryu is hosted in similar volcanic stratigraphy to the historic mine workings located within Japan Gold’s Aibetsu Project, the most prominent of which, Tokusei produced 38,580 ounces of gold and 472,620 ounces of silver between 1930-1942¹. The Metal Mining Agency of Japan completed exploration activities over the Tokusei area between 1998 and 2002, which culminated in five diamond drill holes for a total of 3,300 m with a peak result of 0.95 m @ 69 g/t gold and 263 g/t silver 2 from 500 m along strike of the mine structure.

Mapping from the 1:50,000 scale Japanese government geological map shows three parallel northeast trending altered / mineralized zones over a 2.5 by 2 km zone centered on the Tenryu working now covered by the Japan Gold applications. A combination of stratigraphy, northeast mineralized structures and a lack of modern exploration in the region makes this an attractive exploration target in the Company’s growing project portfolio in Japan.

An initial reconnaissance survey of the area is planned to be completed this year so the project may be ranked against Japan Gold’s other projects for work prioritization.

1Watanabe, 1996. Genesis of Vein-hosting Fractures in the Kitami Region, Hokkaido, Japan. Resource Geology, v46(3), pp 151-166, 1996.

Tenryu Project Area

The Buho Project

The Buho Project comprises four accepted application (1,,324 hectares) located in southwest Hokkaido. The Buho prospect is a vein hosted by high-level alteration on the flank of the Akaigawa inner caldera. There are numerous other precious and base metal occurrences in the area of the caldera complex. Previous drilling by Austpac Resources intersected a north-south vein 140 m  below the main ridge with 3.5 m @ 220 g/t gold and 42 g/t silver, including 0.9 m@ 72.5 g/t gold and 65 g/t silver1.

The scale of the area will allow Japan Gold’s geologists to rapidly complete detailed mapping this year and make decisions for further work requirements including geophysical-electrical methods and ultimately drill testing next year.

1Austpac Gold NL. Company Reports, 1988 to 1994.

The Buho Project Area

 The Onne Project

The Onne Project comprises nine application blocks for a total of 2,998 hectares and hosts the historic Onne gold-silver and Niko mercury mines. At Onne the epithermal quartz veins are developed along east-northeast to east-west orientated structures. Minor production in the years of 1936 and 1928 reported average gold grades of 5 g/t gold and 15 g/t1 gold respectively. At the Niko mine, disseminated cinnabar was mined from an acid altered rhyolite intrusion. Japan Gold will seek to define the limits of the alteration systems around these historically mined vein systems and use surface mapping and geochemistry to target new zones and extensions to previously exploited vein zones for scout drill testing.

1Gold Mines in Japan, The Mining & Materials Processing Institute of Japan, 1990.

The Fujimi Project

The Fujimi Project comprises seven application blocks for a total of 2,201 hectares over the historic Fujimi and No.2 Tateushi gold-silver mines and surrounds. At Fujimi, five quartz veins hosted in rhyolite were mined in the 1930’s minor production records noted an average grade of 15 g/t gold and 20 g/t silver1. The No.2 Tateushi mine had exploration development carried out in the late 1930’s, however this work was probably curtailed by the government moratorium and closure of gold mines in Japan in 1943. Notably, the deeper levels of both of these deposits were not explored and no drilling has been completed here. The Fujimi mercury mine is located immediately to the west of the application area and hot springs are also noted in the valley. The active hot springs are also analogous feature to the Sulphur Creek-Knoxville gold-silver-mercury district. Japan Gold will seek to define the limits of the alteration systems around these historically mined vein systems and use surface mapping and geochemistry to target new zones and extensions to previously exploited vein zones for scout drill testing.

1Sumitoshi Sako, Hiroshi Asai & Tetsusuke Kanayama: Explanatory Text of the 1:50,000 Geological Map of Japan, Kitamifuji area, Hokkaido Development Agency, 1964.

The Harutomi Project

The Harutomi Project, centered around the historic Harutomi mine, consists of five application blocks for a total of 1,672 hectares. The Harutomi mineralization is hosted in the Miocene Konomai formation and was discovered in the late 1930’s, development and production were halted by the 1943 moratorium. Small scale production was carried out between 1960 to 1970 with annual production not exceeding 2,400 tons per year with gold grades between 3.6 to 6.0 g/t gold and 92 to 252 g/t silver1. A total of 10 veins were developed with strike lengths up to 500 m, the average recorded width of the Shikami No. 5 vein was 2.1 m with localized outcroppings up to 10 m wide. A total of 7,810 m of underground workings were developed by the late 1960’s, however exploration was limited to the area of known veins, no exploration drilling has been completed to test deeper extensions and for veins not exposed at surface. Japan Gold will seek to define the limits of the alteration systems around these historically mined vein systems and use surface mapping and geochemistry to target new zones and extensions to previously exploited vein zones for scout drill testing.

1Kiyoshi Hasegawa & Jun Watanabe: Explanatory Text of the 1:50,000 Geological Map of Japan, Tsunemoto area, Hokkaido Development Agency, 1964.

The Onne, Fujimi and Harutomi Project Areas

The Sanru Project

The Sanru Project comprises 35 accepted applications (11,269 hectares) immediately adjacent to the historic Sanru gold mine, which was the second largest producer in Northern Hokkaido. The Sanru mine produced approximately 215,410 ounces at an average grade of 7.4 g/t gold and more than 1.4 million ounces of silver1. The Sanru structure and several other parallel structures host six gold occurrences and are included under the application.

1Watanabe, 1995. Genesis of Vein-hosting Fractures in the Kitami Region, Hokkaido, Japan. Resource Geology, v46(3), pp 151-166, 1996.

The Numanoue Project

The Numanoue Project comprises four accepted applications (1,296 hectares) approximately 8 kms east of the Konomai mine, which produced 2.3 million ounces of gold. The Numanoue mine itself produced approximately 35,365 ounces @ 8 g/t gold and more than 2.6 million ounces @ 815 g/t silver. Japan Gold believes that additional exploration potential remains at the Numanoue deposit and in the area, and intends to follow up with additional exploration.

The Hakuryu Project

The Hakuryu Project comprises 15 accepted applications (4,901 hectares) approximately 1.5 kms south of the Kōnomai mine, which produced 2.3 million ounces of gold between 1917-1974. Eight historic gold working are located within this project. It is underlain by the same host geology as the Kōnomai  mine which consists of the Kōnomai Formation sedimentary rocks which are cut by Late Miocene andesite and rhyolite subvolcanic intrusions.

The Kamitsue Project 

The Kamitsue Project comprises 12 accepted applications (4,069 hectares) approximately 10 km southeast of the Taio mine, Northern Kyushu's largest gold mine which approximately 1.2 million ounces of gold at an average grade of 6.3 g/t and operated between 1903-731,2. Kyushu hosts two other plus million ounce gold producers, the currently producing Hishikari mine with 8.5 million ounces of gold at a grade of 47.3 g/t3 and the Kushikino mine which produced 1.8 million ounces of gold at a grade of 6.7 g/t  between 1914-741,2 in the southern part of the island.

Detailed surface exploration was completed over the Kamitsue area and reported by the Metal Mining Agency of Japan (MMAJ) in the early 1990’s. The Company has inspected several localities with historic workings dating back to the early 1900’s, however no production data is recorded. Regional alteration mapping and soil geochemical sampling reported by the MMAJ covers a 7 km by 4 km area at Kamitsue. This work identified two distinct coincident clay-alteration / geochemical anomalies including a 5.5 km by 1.5 km east-west trending zone with anomalous gold, silver, arsenic, antimony and mercury and a smaller 1.5 km by 0.5 km zone with anomalous gold, silver, arsenic and mercury.

Considering the size of the defined anomalies at Kamitsue, and the other significant gold deposits throughout Kyushu, the Company feels the area has significant merit for further exploration and will commence follow up surface exploration later this year.

1 Garwin, S., et al. 2005. Tectonic Setting, Geology, and Gold and Copper Mineralisation in the Cenozoic Magmatic Arcs of Southeast Asia and the West Pacific, Appendix 1, Economic Geology 100th Anniversary Volume, p 891-930
2Shikazono, N. 1986, Ag/Au Total Production Ratio and Au-Ag Minerals from Vein-Type and Disseminated-Type Deposits in Japan, Mining Geology, 36(6), p 411 – 424
3Sumitomo Metal Mining Co. Ltd. website

Locations of Kyushu Epithermal Gold Projects and Kamitsue Project Area

The Tobaru Project

The Tobaru Project is located in the northern most part of the Hokusatsu-Kushikino mining district and comprises four applications for a total of 1,347 hectares. Significant gold producers nearby include the Fuke and Ohkuchi mines located respectively 1.5 and 4 km west and south of the project. No historic production is recorded at Tobaru but the project applications enclose a large area of alteration hosted in andesite-rhyolite volcanics. The alteration zone is centered on a northeast oriented 1,500 by 700 m zone of silicification and quartz veining which includes pockets of advanced argillic alteration. The core silicified zone is enveloped by argillic and propylitic alteration outwards, and controlled dominantly by steeply dipping fractures1. A study1 of the Tobaru area references a single drill hole located outside the southern margin of the main alteration zone, no other public data on drilling has been sourced to date.  The location of the Tobaru alteration zone within the district makes it a compelling target for further exploration and drill testing.

Hamilton, 1993. Tourmaline and Pyrophyllite-bearing hydrothermally altered volcanic rocks at Tobaru, Japan. Resource Geology Special Issue, No. 14, pp 115-121

The Ohra-Takamine Project

The Ohra-Takamine Project comprises five application blocks for a total of 1,681 hectares over the historic Takamine-Urushi, Takamine and Ohra mines. The project is located 7.5 km south of the historic Yamagano mine which produced 900,000 ounces of gold at a grade of 17.4 g/t. 1,2

Like all of the major gold mines in the Hokusatsu-Kushikino mining district, the Ohra-Takamine project straddles the margin of a gravity-high feature inferred to indicate upward doming of the basement which produced suitable fracture pathways for hydrothermal fluid flow.

Initially discovered in 1885 and mined periodically to 1943 the Ohra mine produced in the order of 27,000 ounces of gold at grades reported between 3.5 to 20 g/t. The northeast striking vein is reported as 1,200 m long with an average width of 0.9 m3,4. Parallel laminated chalcedony boulders inferred to be sinter were noted in the drainages below the mine by Japan Gold geologists, indicating the mineralized system may not deeply eroded.

The Takamine and Takamine-Urushi mines were discovered in latter part of the nineteenth century and mined periodically up to 1943. Takamine mine produced 9,654 tonnes of ore with average grades of 5.1 g/t gold and 28.3 g/t silver. The vein strikes northeast, has a length of 450 m, and average width of 1 m.

Takamine-Urushi mine was estimated to have produced 13,000 ounces of gold between 1896 and 1916. Three northeast striking gold-bearing quartz veins, with lengths up to 350 m were mined, the so-called number 2 vein was reported to carry gold grades between 50 to 100 g/t3,4. Parallel laminated chalcedony boulders inferred to be sinter were also noted at this location, similarly indicating the vein systems are exposed at a high level.

The MMAJ conducted regional and more detailed studies over the Ohra-Takamine area between 1983 and 1989, six drill holes were completed as part of this work. Drill hole 60MAH-2 located to the east of the Takamine-Urushi mine intersected two 10 cm wide quartz veins with respective gold grades of 12.3 and 13.3 g/t, 100 m below the deepest mine workings, and approximately 245 m vertically below surface5.

Due to the high prospectivity of the district and the level of modern exploration completed on this prospects, Japan Gold believes these areas are worthy of more detailed exploration. The Company will seek to define the limits of the alteration around these vein systems by building on the existing data with detailed surface mapping, geochemical-sampling and geophysics to target new zones and extensions to known veins for scout drill testing.

1 Watanabe, 2005. Late Cenozoic evolution of epithermal gold metallogenic provinces in Kyushu, Japan. Mineralium Deposita (2005) 40: pp 307-323
2 Garwin et al. 2005. Tectonic setting, Geology, and gold and copper mineralization in the Cenozoic magmatic arcs of Southeast Asia and the West Pacific. Economic Geology 100th Anniversary Vol. pp 891-930
Michitoshi Miyahisa, 1967: Report of gold deposits survey in Takamine/Ohra district, Kagoshima prefecture, Association of Kagoshima Prefecture mineral resources development promotion.
Gold Mines of Japan, 1989. The Mining & Materials Processing Institute of Japan.
MITI (1984- 1989): Report on the regional survey of the Hokusatsu-Kushikino region, Showa 58 (FY) to 63(FY). Ministry of International Trade and Industry.

The Tobaru andOhra-Takamine Project Areas