The District
The Handeni Gold District in eastern Tanzania contains numerous artisanal gold discoveries over several hundred kilometres. The recent discovery of Magambazi on Canaco's Hadeni Project has brought a great deal of attention to the Handeni Gold District and has upgraded the poorly known area to become a major gold exploration province. Canaco's management has been successful in establishing a large land position in the district.
The Property
The Handeni Gold Project consists of two contiguous claims totalling 100 square kilometres 173 kilometres northwest of Dar es Salam and 35 kilometres south of the town of Handeni. A paved highway is currently being constructed to Handeni, and good quality local roads access workings on both claims.
Ownership
The Handeni Project is 100% owned by Canaco Resources Inc and covers 100 square kilometres.
The Magambazi claim is owned 100% by Magambazi Mines Company Ltd. Canaco has an option agreement to acquire a 100% interest in the Magambazi PMLs subject to cash payments of US$180,000 over two years for the rights to explore and US$1.8 million to acquire a 100% interest subject to a 2% NSR.
The Kilindi claim is owned 100% by Canaco.
History
Gold was discovered in the area in 2003, spurring a gold rush and intense alluvial, then hard-rock mining which remains ongoing at present. A mining village is established at Magambazi, the principal focus of the exploration effort on the Handeni Project.
Recent graduate level research (Kabete et al., 2008) show that the highly-endowed Sukumaland Superterrane, the geological host to Tanzania's most significant gold deposits, has been overprinted on its east-southeastern extension by a Proterozoic orogeny adjacent to the Mozambique belt further east. Newly-recognized gold prospects, exploited on a small scale by artisanal miners, are sited at several locations in this overprinted Archean terrane.
Of particular interest is the well-exposed Magambazi prospect in the Handeni region of the Tanga District. Here, high gold-grade sulfide-bearing quartz veins are enclosed in up to 40 metre thick alteration zones with lower-grade, sulfide-associated gold ore over an exposed strike of several hundred metres, demonstrating its high economic potential. The host rocks and alteration zones are high-grade gneisses with both silicate and sulfide minerals having granulite textures. This, and the absence of strong foliation, suggests a high-grade metamorphic overprint of an originally lower metamorphic-grade orogenic gold deposit. Magambazi thus demonstrates the potential for discovery of world-class, overprinted, Archean orogenic gold deposits in non-traditional exploration terranes in Tanzania.
The Magambazi claims host an active mining operation by local miners. Ore extraction is done by hand and through the use of explosives. Ore is sorted and hand-cobbed at the mine site then transported to the mill site. The mill site consists of seven small mills operating independently. Ore is milled, concentrated by hand, and recovered through the use of a sluice box and mercury.
Geology
The geology of this region represents a non-traditional exploration environment dominated by high-grade metamorphic (granulite to amphibolite facies) rocks which are now thought to be overprinted Achean rocks. The Handeni Project contains a definable stratigraphic sequence with original rock types (pre-metamorphism) including ultramafic to felsic flows and volcaniclastic rocks, black shales and quartz-rich sedimentary rocks. Upper amphibolite facies metamorphism has created a sequence including a variety of rocks including feldspar-quartz biotite gneiss and pegmatite, kyanite and garnet pelite to psammopelite, amphibolites, and pyroxene-olivine ultramafic rocks.
The sequence has been folded into an arcuate shaped synform with a roughly NW-trending axis. Definable structures include ENE-trending thrust faults, NW-trending brittle faults (associated with the Magambazi Main Lodes -- see below), and a series of N-S structures.
Mineralization
Ore-grade gold mineralization is hosted in high-grade metamorphosed mafic to felsic volcanic and sedimentary rocks of Archean or Proterozoic age. Mineralization is vein-related, structurally-controlled, orogenic gold associated with sulfides, including pyrrhotite and arsenopyrite. The dominant host rocks are garnet-silica altered amphibolite, with lesser gneiss (biotite-kyanite-quartz-feldspar). Significant visible gold is present in the mineralized zones.
Recent academic studies (Kabete 2008, age dating) highlight the area as prospective for traditional (but metamorphosed) Achean orogenic gold deposits within the Sukumaland Corridor, the host to major deposits (i.e.Geita, Bulyanhulu, Golden Pride) in the Lake Victoria Goldfields.
The Magambazi deposit is a synformal, doubly-plunging zone of high-grade gold mineralization which is controlled by a NW -trending fault at the intersection of the favourable mafic stratigraphy. The highest-grade shoot component of the deposit lies at the intersection and forms a north-plunging shoot at Magambazi and a south-plunging shoot at Magambazi North. Intense zone of banding-parallel quartz veins are surrounded by siliceous and silica-garnet alteration with significant volumes of arsenopyrite, pyrrhotite, and lesser chalcopyrite and loellingite. Much of the gold is fine-grained free (visible) gold, liberated from the loellignite and arsenopyrite during metamorphism. Several separate zones of ore-grade gold are present between brittle faults which displace the stratigraphy and ore body in several locations.
Exploration
Canaco has been actively exploring the Handeni Project since mid-2007, including acquisition of remote sensing data sets including aeromagnetic data and IKONOS Landsat imagery, mapping, soil sampling, petrology, rock chip sampling, rotary air blast drilling (RAB), reverse circulation drilling (RC), diamond drilling, airborne magnetic and radiometric survey (heli-borne) and detailed induced polarization surveys (IP). Metallurgical studies and scoping work have also been conducted.
In September 2009, Canaco embarked on a major diamond drilling campaign to test two of the more prospective targets: Magambazi and Magambazi North, about one kilometre northeast of Magambazi. Canaco was immediately successful, with spectacular intercepts of gold from both the Magambazi and Magambazi North targets. The best intercepts to date from diamond drilling at Magambazi include:
- 59.0 metres at 4.28 g/t gold (MGZD0001)
- 39.6 metres at 3.56 g/t gold (MGZD0007)
- 56.0 metres at 6.34 g/t gold (MGZD0012)
- 30.3 metres at 3.46 g/t gold (MGZD0018)
- 21.2 metres at 4.8 g/t gold (MGZD0043)
- 21.7 metres at 5.45 g/t gold (MGZD0045)
- 37.0 metres at 12.45 g/t gold (MGZD066)
- 32.0 metres at 9.27 g/t gold (MGZD073)
- 27.0 metres at 4.27 g/t gold (MGZD0079)
Preliminary metallurgical test work was completed using a bulk sample of approximately 380kg with crushing to a nominal 74μm (200 mesh) and gravity separation, followed by an eight-hour bottle roll leach. Highlights from the metallurgical test work include:
- Gold recovery of 94.14% obtained using a combination of gravity separation and cyanidation;
- The majority of gold extracted using gravity separation with 72.59% of the gold recoverable as free gold; and,
- No refractory issues with respect to the ore grade mineralization
The preliminary metallurgical test work program was conducted in China at the Northwest Geological Institute for Non-Ferrous Metals under the supervision of Senior Engineer, Dr. Zhengtao Liu.
Other work outside of the Magambazi discovery has defined a 12 kilometrelong trend (the MK Trend) of anomalous gold geochemistry in soils. The Handeni Gold trend is now recognized as consisting of two, parallel gold trends with a combined strike length of over 15 kilometres. Three high-priority targets are defined along the MK Trend, supported by soil geochemical anomalies, magnetic and IP targets, and artisanal workings including bedrock and alluvial operations.
- Kwadijava is the site of extensive shallow bedrock gold workings, strong soil geochemical anomalism, a strong magnetic target to the north of the workings, and IP anomalies down dip of the actual outcrop expression of the workings. Peak rock-chip results from channel sampling of the shallow artisanal workings in bedrock mineralization are 10 metres at 2.54 g/t gold and two metres at 14.3 g/t gold. RC drilling in 2008 intersected 12 metres at 1.04 g/t gold from 25 metres, but much of the RC drilling was targeting a deep extension to the surface mineralization. Instead, new data highlight a potential shallow-plunging shoot and additional disconnected targets at depth.
Exploration is ongoing with synchronous programs of grass roots exploration via RAB and RC drilling of geochemical and/or geophysical targets to resource diamond drilling at Magambazi and Magambazi North.
