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 淘金者的梦想家园，你愿意与之失之交臂吗？ |
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jackiewindy
头衔: 海归中士
加入时间: 2006/06/28
文章: 8
海归分: 823
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作者：jackiewindy 在 项目找投资与合作 发贴, 来自【海归网】 http://www.haiguinet.com
在苏丹拥有几处金矿的开发权，愿意寻求有实力的合作者合股
开发经营，国际金价扶摇直上，我们可以成就这个时代的淘金梦。
详情清联系 [email protected] 谢谢
Location and accessibility: The abandoned Abu Sari Gold Mine is in a hilly district 7 km East of Abu Sari village at the Nile River. The approximate coordinates of the mine workings are latitude 20º 17' N and longitude 30º 37'E.
Access to the area from Omdurman is by asphalt road to El Debba, unpaved road to Delgo after crossing the Nile by a ferry to the right bank of the River Nile and by motorable track to Abu Sari. The trip is about 12 hours driving. The surface area is about 6250 km² (Fig. 1).
Geological Setting: The Abu Sari Block covers the southwestern end of a large belt of Neoproterozoic island arc that through crustal accretion, during the Pan–African orogenic event (Kröner, 1985, Vail 1988) were involved in the formation of the Arabian –Nubian Shield. It was accreted in the late Neoproterozoic against the Nile Craton to the west. The characteristic lithological formations participating in the belt are: high grade basement, island arc volcano-sedimentary series that display green schist facies metamorphism, ophiolite and subduction–induced batholiths.
Mineralization: Gold mineralization occurs in bluish gray and milky quartz veins, lenses and stringers ranging in thickness from 0.5m to 3m with a maximum length of 1.5 Km. The mineralized veins show vertical and lateral changes in geometry and composition. They are generally semi-concordant with the regional trend of the volcanosedimentry sequence and occur either as highly folded, sheared and brecciated quartz veins, sub-vertical massive ridges northerly dipping (70º-85º) or composite veins comprising a series of en echelon lenses. The contact zone between quartz veins and the host rocks shows ferruginous alteration. This zone has been mined out along with quartz veins indicating the presence of local gold enrichment.
Mining History and Exploration: Gold mining at Abu Sari dated from Pharoanic period (New Kingdom). The ancient mining activity was limited to the exploitation of small quartz veins and some placer excavations. During the period from 1901 to 1904 the mine was initially explored and developed by the Nuba (Sudan) Development Company. However the records during this period are vauge. The mine was reworked in 1940s by Bishop, manager of the Gebeit Mine, up to his death in 1953. The company did some exploration work as four shafts were dug and a milling and a processing plant were installed near Abu Sari village.
In the early eighties the mine was visited by Minex Company staff and some rock samples were collected for gold content assay. In 1985 the area was studied by Bonifica-Geoexpert as part of their hydrogeological studies and investigations in Northern Sudan. The maximum Au value of 34.5 g/t was found in vein gaartz.
About 20 rock samples were collected from the mine area by UNDPCD in 1986, 7 quartz veins samples have gold values ranging from 0.024g/t to 4 g/ t and 3 samples from alteration zones have an average gold value of 5.49 g/t and a value of 44.9 g/t for fragment of quartz dumps material.
A Geological Research Authority of the Sudan (GRAS) team (Sammani et al. 1993) undertook a geological survey consisting of detailed mapping and topographic contouring of the mining area, which was divided into four blocks namely Block A to Block D (Fig.2). Semi-detailed exploration work include trenching and pitting was conducted. A total of 185 rock samples and 76 heavy mineral concentrates wer collected as well as 32 rock specimens for petrographic study. Several rock samples yielded values above 10 g/t with a maximum value of 40.3 g/t Au.
China Devro Gold Group Co. Ltd. held a gold concession on the Abu Sari Block in 1999 and carried out a detailed exploration work included:
- Detailed mapping of Abu Sari mine area.
- Regional geochemical rock sampling.
- Their results showed gold anomalies in the vinicity of the Abu Sari and Tiniary Mines.Hand-dug trenching with channel sampling .
- Drilling of 7 inclined core drilled holes to investigate the quartz veins near shaft No. 4.
The mineralization was intersected at depths between 40 and 120m, having an average grade of 2.5 g/t Au and maximum value of 21.83 g/t Au. Devro`s conclusion was that there is a low-grade large tonnage deposit.
Recently, the Nubian Desert Gold Project (NDGP) (Sudanese French Joint Venture) was awarded an Exclusive Prospecting Licence (EPL) by GRAS to explore for gold on Abu Sari Block (Jolly and Urien, 2002). The conducted work programme included:
1- A regional wadi sediments geochemical sampling at a density of 1 sample per 6.8 km followed by semi-detailed stream sediments sampling.
2- Re-sampling of previously hand dug 84 trenches where 76 samples of the 517 collected samples yielded a gold grade more than 1 g/t . These included 7 samples between 5 g/t and 10 g\t . and 7 samples exceeded 10 g/t and the maximum gold value was 65.72 g/t.
3- 18 inclined reverse circulation (RC) boreholes were conducted to check the potential of the veins that were not studied by Devro (Fig.2). The intersected mineralization is hosted by 2m to 4m thickness and gold grades range between 1.27g/t and 9.21 g/t with 6 intersections of 2m width showing a gold grade ranging between 5.34g/t and 9.21 g/t. This target warrants further drilling to better define its potenti
References :
- Bonifica-Geoexpert (1986): Primary and alluvial gold deposits along the Nile Valley as part of hydrogeological studies and investigations in Nothern Sudan; National Water Cooperation, Ministry of Energy and Mining, Khartoum, p. 77.
- China Devro Gold Group Co. Ltd. 1999. The technical report of geological exploration in Abu Sari concession, Northern Sudan 1998-1999, (unpubl.report p.30, handed over to GRAS).
- Jolly ,J.and Urien, P. 2002. Nubian Desert Gold project (Sudan ). Sixth campaign 2001-2002. BRGM/RC-51709-FR, p. 120.
- Kröner A. (1985): Ophiolites and the evolution of tectonic boundaries in the Late Proterozoic Arabian–Nubian Shield of Northeast Africa and Arabia. Precambrian Res. 27, pp, 277-300.
- Sammani, K. Z., Mohammed, E.K., Fadl, S.E.A., and Abu Fatma, M. (1993). Geology of Abu Sari Gold Mine (unpubl.) GRAS report, p. 41.
- Vail , J.R. (1988). Tectonics and evolution of the Proterozoic basement of northeastern Africa. In: EL Gaby S., Greiling R O., (eds.). The Pan-African belt of Northeast Africa and Adjacent areas, Vieweg, Wiesbaden, pp. 195-226.
United Nations Department of Technical cooperafion for development, (1986). Mineral exploration of Egypt /Sudan area of integration.UNDTCD, New York.Report n DP /RAB-80-014/2,
Commodity: Gold-Copper
Locality: Komatit Prospect (Block 10)
Introduction : The Komatit prospect is located at Lat. 19° 47¢N and Long. 35° 08¢E in the southern margin of the Gebeit Terrain. It is 300km west of Port Sudan. The southern margin of the Gebeit Terrain of the Nubian Shield contains a slightly recrystallized and deformed younger arc series. The series is made up of intermediate and acid volcanic and volcaniclastic rocks and their equivalent intrusives. Similar younger arc assemblages host and occur around the Mahd Edahab epithermal deposit of Saudi Arabia on the eastern side of the shield.
Geological setting: The Komatit prospect is hosted to slightly deformed layers with commonly porphyritic andesite, dacite and rhyodacite associated with coarse-grained breccias or tuffs with chert fragments, and chert-like siliceous layers (Fig. 1). Porphyritic diorite and microdiorite have intruded the volcanic rocks, which are locally pyritic, and grading into gabbroic rocks. A main dyke network commonly made up of porphyritic microdiorite or dolerite, striking N 60° or N 160° intersects both of the host rocks and the adjacent diorite. The dykes (0.5 to 2 m thick) and the density number 2 –3 dykes per 10m in between the diorite and the volcanic. The main phenomenon affecting all these formations is an intense hydrothermal alteration expressed in the formation of kaolin, limonite, sercite, epidote, and sulphide boxworks. This alteration affects an extensive zone extending over 4 km E-W and 2-km N-S.
Dmineralisation: The Komatit prospect was first recorded by a team of geologists from the Geological and Mineral Resources Department (GMRD), now GRAS, during a regional mapping of the northern part of Wadi Amur Sheet (Hassan, et al, 1983). They observed mineralisation of gold, pyrite, chalchopyrite, malachite, and azurite. Hydrothermal alteration expressed by kaolin, limonite, siderite, epidote and sulphide boxworks has affected the volcanic and dioritic rocks. Malachite impregnation is commonly recorded close to the dykes. Sulphide boxworks are widely scattered and fresh pyrite is found in cherty tuffaceous layers. Haematite is frequently occurring associated with volcanic rocks. The altered surface is very extensive (8km2) and is partially surrounded by a large area of ancient alluvial workings.
Later, the Komatit prospect has been investigated during the tenure of the Sudanese – French Technical Cooperation Project (1976-1986). Surface geology and preliminary prospection indicate that the area is highly potential for copper and gold by analogy with occurrences of the same type discovered in a similar series at Khor Arba’at area (Braux et al, 1983).
Another zone of ancient alluvial workings has been found 10-km southwest of the Komatit Prospect. The occurrence is hosted by a series similar to that of Komatit with an alteration zone of about 2 km2.
Chemical analysis: A very rapid exploration of the Komatit Prospect was done by Braux et al. (1983). Five samples of the mineralized zone were collected for multi-elements analysis for Cu, Zn, Pb, Au, Ag, and As. The results are presented in Table (1).
Table (1) : Results of chemical analysis of Cu, Zn, Pb, Au, Ag, and As (in % and ppm)
Sample No. Cu Zn Pb Au Ag As
7585 1.91% 7 70 0.46 2.2 7322
7587 4431 7 169 0.7 3.3 4050
7588 02% 24 13 £ 0.1 1.1 293
7589 1.22% <5 91 0.95 8.0 5267
7598 5.61% 165 32 £ 0.1 2.3 287
Thierry et al (1984) commenced a geological prospecting on the same area. A total of 121 rock samples were collected from three cross-sections, representing all the rock types in the area. The samples were analyzed for Au and Ag. 98 samples show gold grade lower than or equal to 0.1 g/t and 5 exceed 0.3 g/t.
Infrastructure: The Komatit Prospect at the eastern part of block No. 10 (Fig. 2) is 300 km from Port Sudan and can be reached through an all season motorable road. Water could be obtained from Bir Komatit, which is about 30-km southwest of the prospect. Skilled to semi-skilled labourers are available.
Discussion: According to Thierry et al, (1984) the characteristics of this prospect are similar to those of Cu porphyry deposits, with subordinate Mo or Au, related to the subvolcanic calc-alkaline intrusions emplaced in andesite series (active continental margins or and island arc environment). However, we believe that there are similarities between the Komatit and Mahd Edahab deposit on the eastern part of the shield, in the host rocks, alteration zones, surface expressions, and tectonic setting. This suggests a possible epithermal origin for the Komatit prospect.
References:
- Braux, C. Cottard, F., and Osman, M.A., 1983, Cooperation Program of Mineral Research in Sudan. Red Sea Project. Mineral Exploration Results in Wadi Amur area, BRGM report 83 SUD 005.
- Hassan, A. S.; Abd El Hafiz, A. E.; Mustafa, O. M.; Elsheikh, A. E.; El Amin, O.; Elsheikh, A.; Thongang, T. O.; Mustafa, A.; Abd Al Gadir, H. A., Kazim, M. M., 1983, Report on the Geology of the Northern Part of Wadi Amur (Sheet 45D). Unpublished GRAS report. Commodity: Gold-Copper
Locality: Komatit Prospect (Block 10)
Introduction : The Komatit prospect is located at Lat. 19° 47¢N and Long. 35° 08¢E in the southern margin of the Gebeit Terrain. It is 300km west of Port Sudan. The southern margin of the Gebeit Terrain of the Nubian Shield contains a slightly recrystallized and deformed younger arc series. The series is made up of intermediate and acid volcanic and volcaniclastic rocks and their equivalent intrusives. Similar younger arc assemblages host and occur around the Mahd Edahab epithermal deposit of Saudi Arabia on the eastern side of the shield.
Geological setting: The Komatit prospect is hosted to slightly deformed layers with commonly porphyritic andesite, dacite and rhyodacite associated with coarse-grained breccias or tuffs with chert fragments, and chert-like siliceous layers (Fig. 1). Porphyritic diorite and microdiorite have intruded the volcanic rocks, which are locally pyritic, and grading into gabbroic rocks. A main dyke network commonly made up of porphyritic microdiorite or dolerite, striking N 60° or N 160° intersects both of the host rocks and the adjacent diorite. The dykes (0.5 to 2 m thick) and the density number 2 –3 dykes per 10m in between the diorite and the volcanic. The main phenomenon affecting all these formations is an intense hydrothermal alteration expressed in the formation of kaolin, limonite, sercite, epidote, and sulphide boxworks. This alteration affects an extensive zone extending over 4 km E-W and 2-km N-S.
Dmineralisation: The Komatit prospect was first recorded by a team of geologists from the Geological and Mineral Resources Department (GMRD), now GRAS, during a regional mapping of the northern part of Wadi Amur Sheet (Hassan, et al, 1983). They observed mineralisation of gold, pyrite, chalchopyrite, malachite, and azurite. Hydrothermal alteration expressed by kaolin, limonite, siderite, epidote and sulphide boxworks has affected the volcanic and dioritic rocks. Malachite impregnation is commonly recorded close to the dykes. Sulphide boxworks are widely scattered and fresh pyrite is found in cherty tuffaceous layers. Haematite is frequently occurring associated with volcanic rocks. The altered surface is very extensive (8km2) and is partially surrounded by a large area of ancient alluvial workings.
Later, the Komatit prospect has been investigated during the tenure of the Sudanese – French Technical Cooperation Project (1976-1986). Surface geology and preliminary prospection indicate that the area is highly potential for copper and gold by analogy with occurrences of the same type discovered in a similar series at Khor Arba’at area (Braux et al, 1983).
Another zone of ancient alluvial workings has been found 10-km southwest of the Komatit Prospect. The occurrence is hosted by a series similar to that of Komatit with an alteration zone of about 2 km2.
Chemical analysis: A very rapid exploration of the Komatit Prospect was done by Braux et al. (1983). Five samples of the mineralized zone were collected for multi-elements analysis for Cu, Zn, Pb, Au, Ag, and As. The results are presented in Table (1).
Table (1) : Results of chemical analysis of Cu, Zn, Pb, Au, Ag, and As (in % and ppm)
Sample No. Cu Zn Pb Au Ag As
7585 1.91% 7 70 0.46 2.2 7322
7587 4431 7 169 0.7 3.3 4050
7588 02% 24 13 £ 0.1 1.1 293
7589 1.22% <5 91 0.95 8.0 5267
7598 5.61% 165 32 £ 0.1 2.3 287
Thierry et al (1984) commenced a geological prospecting on the same area. A total of 121 rock samples were collected from three cross-sections, representing all the rock types in the area. The samples were analyzed for Au and Ag. 98 samples show gold grade lower than or equal to 0.1 g/t and 5 exceed 0.3 g/t.
Infrastructure: The Komatit Prospect at the eastern part of block No. 10 (Fig. 2) is 300 km from Port Sudan and can be reached through an all season motorable road. Water could be obtained from Bir Komatit, which is about 30-km southwest of the prospect. Skilled to semi-skilled labourers are available.
Discussion: According to Thierry et al, (1984) the characteristics of this prospect are similar to those of Cu porphyry deposits, with subordinate Mo or Au, related to the subvolcanic calc-alkaline intrusions emplaced in andesite series (active continental margins or and island arc environment). However, we believe that there are similarities between the Komatit and Mahd Edahab deposit on the eastern part of the shield, in the host rocks, alteration zones, surface expressions, and tectonic setting. This suggests a possible epithermal origin for the Komatit prospect.
References:
- Braux, C. Cottard, F., and Osman, M.A., 1983, Cooperation Program of Mineral Research in Sudan. Red Sea Project. Mineral Exploration Results in Wadi Amur area, BRGM report 83 SUD 005.
- Hassan, A. S.; Abd El Hafiz, A. E.; Mustafa, O. M.; Elsheikh, A. E.; El Amin, O.; Elsheikh, A.; Thongang, T. O.; Mustafa, A.; Abd Al Gadir, H. A., Kazim, M. M., 1983, Report on the Geology of the Northern Part of Wadi Amur (Sheet 45D). Unpublished GRAS report.
- Thierry, R., Lasserre, J. L., and Cortial, P., 1985. Cooperation Program of Mineral Research in Sudan. Red Sea Project. Mineral Exploration for Gold (Hamissana, Tohamyam, Komatit, Ashash - Igarairi). BRGM Report 84 SUD 002.
- Thierry, R., Lasserre, J. L., and Cortial, P., 1985. Cooperation Program of Mineral Research in Sudan. Red Sea Project. Mineral Exploration for Gold (Hamissana, Tohamyam, Komatit, Ashash - Igarairi). BRGM Report 84 SUD 002.
作者：jackiewindy 在 项目找投资与合作 发贴, 来自【海归网】 http://www.haiguinet.com
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 淘金者的梦想家园，你愿意与之失之交臂吗？ -- jackiewindy - (17357 Byte) 2006-6-30 周五, 03:58 (2280 reads)
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