The Qinling Mountains form the boundary between the North China and Tarim Cratons to the north and the Yangtze Craton and Tibetan Plateau to the south. The mountains consist of an east-west trending Upper Paleozoic-Mesozoic thin-skinned fold and thrust system formed by north-south compression. Devonian sedimentary formations consist of fine grained clastic sediments, calcareous sandstones, shales and various types of limestone. Younger Triassic assemblages consisting of sandstone, slate and limestones have been inserted into the Devonian section by complex, north verging thrust faulting.
Younger Mesozoic calc-alkaline intrusions are common in an east-west trending belt in the northern part of the region. Precambrian intermediate to basic volcanics form the core of an anticlinorium which is exposed in the southern part of the area of interest.
Yangshan Gold Belt - Longnan Project
Location
The Gansu Longnan Properties are located in Gansu Province, within the southwest Qinling gold field, in China.
The Longnan project has been divided into three sub-projects according to geographic distribution, type, and potential of mineralization:
- Yangshan: including five exploration permits located in the northeast extension of the Yangshan gold belt and its adjacent area; potential for gold.
- Yejiaba: including four exploration permits located to the north of the Yangshan exploration permits; potential for gold and antimony.
- Xicheng East: including three exploration permits to the east extension of the famous Xicheng Pb-Zn mineralization belt; potential for gold, silver, lead and zinc.
Work Program - All sub-project areas
- Follow up on the regional stream sediment anomalies will be continued over all three sub-project areas
Work Program - Yangshan sub-project area
- Mapping, sampling & trenching on top showings
- Geophysics (IP) program on Yangshanli for drill target definition
Ownership
Minco Gold's wholly-owned subsidiary, Minco China, presently holds the 12 exploration permits (in 3 sub-project areas) in the Longnan region of south Gansu Province, within the southwest Qinling gold field, in China.
Background
In August 2005, the Company initiated a regional stream sediment geochemical survey within the Yangshan, Yejiaba, and Xicheng East permits. The survey covered approximately 913 km2 and involved the collection of 3,036 stream sediment samples from active drainages. Twenty geochemical anomalies (gold, arsenic, antimony, and silver) were delineated in the famous Yangshan gold trend, 12 geochemical anomalies in Yejiaba area, and 11 anomalies in the Xicheng East area.
Geology and Mineralization
All thirteen exploration permits are located over regional geochemical gold anomalies with host rocks and structures similar to other gold deposits in the region. The local geology and exploration results within the three sub-project areas are described below.
Results
Exploration programs in 2006 focused on the most significant anomalies. Infill sampling, geological mapping, and trenching programs were conducted over the areas of interest and evidence of gold, silver, antimony, lead, and zinc mineralization has been discovered in all the three sub-project areas.
Yuezhao Permit - The 12 km2 Yuezhao permit belongs to the Yangshan sub-project area. Gold mineralization at an abandoned tiny pit at the Yuezhao gold occurrence is more than 10 metres in width and contains samples ranging from 1.0 to 7.3 grams per tonne gold and two mineralized zones can be traced along strike. Zone ZT-1 has been traced for about 1,000 metres (m) at surface along the NE60-70° strike direction and varies from 2.0m to 3.6m in width with an average gold grade of 1.52 grams per tonne (g/t). Zone ZT-2 was located 35m north of zone ZT-1, has been traced for more than 400 metres, and varies in width from 1.3m to 6.1m with an average gold grade of 3.54g/t.
- Yangshanli Permit - The 42 km2 Yangshanli permit belongs to the Yangshan sub-project area. Stream sediment sampling outlined a number of strong gold, antimony, and arsenic anomalies. Nine composite Au-As-Sb-Ag anomalies have been delineated in the Yangshanli permit area and peak values from 0.1 to 0.8g/t gold have been detected in soil samples in most of these soil anomalies. Five alteration and mineralization zones, characterized with structural breccias, chloritization, silification, pyritization, limonitization, and anomalous gold from 0.1 to 0.65g/t in silty phyllite and phyllite, have been delineated within the gold anomalies. Preliminary follow up for the area where a peak gold value of 0.8g/t was detected in soil has defined an alteration zone of 400m in length and more than 10 meters in width. A gold mineralization zone of 200m in length and 1 to 2m in width with grades ranging from 1 to 3g/t was further delineated within the alteration zone.
- Chachashi Permit - The Chachashi permit belongs to the Xicheng East sub-project area where a significant anomalous zone measuring 1000m in length and 400m in width was contoured with a threshold of 0.5g/t silver in soil samples at the contact zone between a granite intrusion and the Proterozoic metamorphosed siltstone and sandstone. 12 soil samples within the anomaly contain 5 to 15g/t silver and 0.1% lead and zinc.
