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Progress in Exploration of the Wulagen Pb-Zn deposit, Xinjiang, NW China Beijing Non-ferrous Metals Exploration Center 2007/11. Contents. 1. D iscovery H istory 2. Geological Characteristics 3. Enlightenment of Exploration 4. Outlook. 1 、 Discovery H istory of the Deposit.
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Progress in Exploration of the Wulagen Pb-Zn deposit, Xinjiang, NW China Beijing Non-ferrous Metals Exploration Center 2007/11
Contents 1. Discovery History 2. Geological Characteristics 3. Enlightenment of Exploration 4. Outlook
1、DiscoveryHistory of the Deposit The Wulagen Pb-Zn deposit is located on about 6km to the south of Kangsu, Wuqia county, Xinjiang, and there is a highway to the camp.
Discovery History • In 1943, the mineralized outcrop was discovered in the Wulagen district, which was recorded as a Pb-Zn occurrence in the map of regional geology and resources at scale of 1:1,000,000. • 1951-1961, this occurrence had been evaluated by the Kashi Mining Management Office, and the 702 Geological Party of Non-ferrous Resources. The main goal at that time was to prospect the breccia-type Pb-Zn ore deposit hosted by carbonate rocks in the northern ore zone, and the metal reserves of No.1 orebody are as follows: 11,300 tons Pb @ 5.8%, 17,400 tons Zn @ 7.43%. • 1958-1963, the deposit had been mined at small scale. • 1962-1998, there was no further prospecting in this area due to the restricted understanding of this deposit as a small hydrothermal deposit.
Discovery History • 1999-2000, Xinjiang Xinhui Geology and Mining Corporation (the predecessor of the Xinjiang Institute of Geological Survey, the China Geological Survey Center for Non-ferrous Resources) had carried out geological survey in the Wulagen district and adjacent area, and the deposit was thought to be possessing the characteristics of strata-bounded ore deposit, which was similar to that of the Jinding large Pb-Zn deposit in Yunnan province, and then, the sandstone-type ores were determined to be of good potentiality. • 2001-2002, a project from the China Geology Survey, named as “the Resource Potentiality Assessment of Pb-Zn Polymetal Minerals in the Wuqia area, Xinjiang”, had been carried out by the Xinjiang Institute of Geological Survey, the China Geological Survey Center for Non-ferrous Resources. Based on the surface survey, a drill hole (ZK0-1) had been finished in the southern ore zone, discovering the large-sized orebody with apparent thickness of 254m (true thickness of 194.10m), and the average grades are of 0.53% for lead, and 4.34% for zinc, implying a good perspective as a large deposit.
The profile of No.0 prospecting line in the southern ore zone Ore thickness is 48.94m on surface,with grades of 0.38%Pb, and 3.13%Zn. Drill holeZK0-1: apparent thickness is 254m, and 194.10m for true thickness, with average grades of 0.53%Pb, and 4.34%Zn. Depth is 70m (tunnel), thickness is 84.56m, with grades of 0.30%Pb, and 3.76 %Zn.
Discovery history • 2004-2007, a project from the China Geology Survey, named as “the Resource Investigation and Assessment of Pb-Zn-Cu Minerals in the Wuqia-Atushi area, Xinjiang”, has being carried out by the Xinjiang Institute of Geological Survey, the China Geological Survey Center for Non-ferrous Resources. The perspective of Wulagen Pb-Zn deposit has been preliminary controlled, and some investigation and assessment works have also been carried out in the adjacent area. • So far, the proved reserve of Pb+Zn is of 4Mt at class of 333+3341, which is expected to be over 5Mt after further prospecting work in the Wulagen mine site. Besides, some new occurrences are discovered in the adjacent area, such as Kangxi, Wudong, Yangbei, Jiang’ejie’er and Tuopa, and so on.
2. Geological Characteristics (1) Strata:The host rocks are light grey sandstone and pebbled sandstone of Palaeocene Wulagen Formantion (E1w). Proterozoic metamorphic clastic rocks Ore-bearing strata Cretaceous peliticsiltstone Fault Fault E1w The south limb of the Wulagen syncline
The Wulagen Formation is divided into three parts: Part 1 (E1W1) is ore-bearing glutenite. E1W2 E1W3 Part 2 ( E1W2) is the hanging wall consisting of mudstone and marl sandwiched with gypsum. Part 3 (E1W3) consists of marl and limestone with fossil of brachiopods, which shows the transgression sequence. E1W1
Geological Characteristics (2) Structure:The deposit is controlled by the Wulagen syncline, which is divided into two ore zones, the northern zone and the southern zone. The northern ore zone is 3000m long, consisting of three orebodies. 康 苏 Kangsu River 河 The southern ore zone is 3500m long, consisting of three orebodies.
Q E1w Outlook of the Wulagen syncline The dip of north limb is steeper than that of the south limb. The syncline is unconformable overlaid by the Quaternary (Q) Xiyu conglomerate.
(3)Orebody:The stratiform, stratiform-like orebodies are accordant with the host strata. No.1 orebody is 3500m in length with average thickness of 15.80m, and average grades of 0.70% Pb, 3.55%Zn, and 4.25%( Pb+Zn). The second part of the No.2 orebody is located on prospecting lines of 47-71 ,which is 800m in length and 9.62m in thickness, and grades are of 0.47%Pb, 1.75%Zn, and 2.22%(Pb+Zn). No.3 orebody is located on prospecting lines of 0-8, which is 400m in length and 27.07 in thickness, and grades are of 0.55%Pb, 4.13%Zn, and 4.68%(Pb+Zn).
The profile of prospecting line 7 in the southern ore zone Inclined depth controlled : 510m; Orebody elevation: 1860m; Horizontal thickness: 52.35m; Pb average grade: 0.75% Zn average grade: 2.50% Pb+Zn grade: 3.25% Maximum of single sample: Pb: 1.70% Zn: 2.54% Pb+Zn: 4.24% SZK7-1 Metal mineral assemblage is simple, and the main minerals are sphalerite, galena and pyrite.
A B (4) Ore types: A: the oxidized sandstone (containing gravel) type ore on surface. B, C:the primary sandstone (containing gravel) type ore. Sandstone type ore mainly consists of sphalerite. C
Breccia type ore : Locally occurred in the brecciated marl on the top of sandstone type ore, which is relatively rich in lead.
A:the massive galena vein is occurred locally on the north limb. B:the bedded gypsum occurred in the hanging layer of the ore-bearing strata is distributed extensively in mine site. C: the brecciaed gypsum layer. A C B
I III II A (5) Host Rock Alteration A:the fading in footwall strata of northern ore zone I-ore-bearing sandstone; II-fading alteration of Cretaceous mudstone in the footwall; III- Cretaceous claret mudstone (country rock). B B:the dolomitization of hangingwall marl on the top of ore-bearing glutenite in the southern ore zone.
The table of evaluated resources reserve Reserve of Pb-Zn ore (ten thousands ton) Reserve of Pb+Zn (ton) Average grade (×10-2) Number of orebody Reserve type Metal reserve (ton) Ore zone Mark Two parts Southern ore Zone total Northern ore zone total Up to 2006
The profile of drilling hole ZK1 in the core of the Wulagen syncline The drilling in 2007 shows that orebodies within two limbs are combined with each other at depth, so that the resource potential is expanded remarkably. The proved reserve (333+3341) is over 4 Mt, and the perspective reserve is over 5 Mt.
Distribution map of drilling project There is still great prospecting potential in the Wulagen camp SZK39-1 NZK24-1 NZK56-1 ZK1 SZK0-2 SZK0-3 SZK70-1 SZK7-1 SZK15-1 SZK0-1
2. Geological Characteristics • The Wulagen deposit is characterized by large scale and steady minerlization. • Based on the geological characteristics, a two-stage mineralization model is suggested: • From Later Mesozoic to Early Cenozoic, this area experienced sedimentary processes from continental facies to shallow marine facies in the regional extension regime, resulting in the extensive hot brine activity. • In Later Paleocene, affected by the collision between India plate and Eurasian plate, the ore-bearing hot brine was extracted and moved to the favorable site to form the Pb-Zn deposit, and the pebbled sandstone layer of Wulagen Formation within impermeable layers (mudstone) became the favorable site for mineralization of ore-bearing hot brine by way of infiltration and replacement.
3. Enlightenment of Exploration (1) To reasonably select the target area is the base for ore prospecting There are many ages (Pt,D,C,E) and many types of Pb-Zn mineralization in the western margin of the Tarim basin, where there are the features of the large-scale ore concentration area. However, the geological work in this area is still poor now, so that further work should be carried out to discover large Pb-Zn deposits.
(2) It is the key to ore prospecting that to exactly understand the ore deposit type, and choose the right technique method (combination). • In the past, the Wulagen deposit was accounted as a small hydrothermal deposit with little perspective. After our survey, we recognize that the deposit has the similar characteristics to that of Jinding strata-bounded deposit, and has the favorable ore-forming conditions of large deposit. • In the past, the prospecting mainly focused on the mineralization of breccia type ore at small scale. Through geology and geochemistry survey on the profile, we have discovered the large-scale mineralization of sandstone type that is not easy to recognized on surface, and put this ore type as the main prospecting object. • Due to the natures of precipitous topography, low content of sulfide,and the ore-bearing layer together with gypsum layer, we choose the method of primary halo exploration to quickly block out the enriching section of ore-bearing strata. We employ the geological mapping, geochemical exploration and engineering verification as the main evaluation means.
(3) Strengthening the study on minerogenetic (ore controls) regulations, and choosing the key engineering for verification, are the effective ways to enhance our confidence of ore prospecting, and expand the resource reserve. • Based on the knowledge of the mineralization and the thickness of ore-bearing sandstone (conglomerate) layer in Wulagen deposit, we chose the key position to drill a core (ZK0-1) for verification with the annual appropriation of only 0.6 million Yuan. The core reveals the orebody of 194m in thickness, with average grade of 4.87% for Pb+Zn, showing large perspective of the Wulagen deposit (>0.5Mt). • Based on the knowledge of the orebody controlled by a syncline, we verify our idea at the rising ends of the syncline, and the orebodies of north and south ore zones are proofed to be combined with each other at depth, which expands remarkably the resource reserve and the space for searing new orebody.
(4) Persistent support and effective guidance from the China Geology Survey guarantee the achievement of ore-searching breakthrough in this area. (5)Public geology work promotes the business geology work,whcich is an important approach to accelerate the transformation of exploration results. Mine office building Gate of mine site A large-scale Pb-Zn mine is in accelerating construction
Geological map of Wulagen Pb-Zn deposit in Wuqia county, Xinjiang 4. Outlook To the west region of the Wulagen Pb-Zn deposit, there are same ore-bearing layers and similar mineralization characteristics. Three Pb-Zn ore belts have been discovered, including KANGXI section (the west extending part of the northern zone), (the southern zone )XIYAN section and WUDONG section( subsidiary anticline of the synclinorium ), which have a great potential for prospecting. WULAGEN mine site
KANGXI lead-zinc occurrence The length of the northern mineralized body is about 1200 meters and average thickness is 10.50 meters. Average grades are of 0.36%Pb, and 1.41%Zn. Kangxi is located at western extending part of the northern zone , and there occurred the same strata. The length of the mineralization zone is about 8 kilometers and the width is 150 meters. Mineralization mark have been discovered on surface, and this area has a large prospecting potential. The length of the middle part mineralized body is about 3200 meters and average thickness is 32.54 meters. Average grades are of 0.23%Pb,and 1.24%Zn. The length of the south mineralized body is about 1600 meters and average thickness is 16.23 meters. Average grades are of 0.50%Pb, and 2.76%Zn.
There extensively exist the similar mineralization conditions to those of the Wulagen deposit in the western of Tarim basin. The Kashi depressionin the west fringe of Tarim basin was formed in late Mesozoic–early Cenozoic extension regime, which is a compound rejuvenated basin at the continental margin. The length is 300 kilometers and width is 50-150kilometers. In Paleocene epoch, the intrusion of Tethys seawater formed vast semi-hermetical -hermetical marine basin and provide condition to form widely thermal brine activity. Subsequently, during the conversion period from compression to extension, ore-bearing hydrothermal brine had been extracted and transported to be deposited. Transgression range The sketch mapof the Kashi depression
In the Kusilapu Pb-Zn belt, located on the piedmont zone of West Kunlun in the southwestern margin of Tarim Basin, the MVT mineralization are developed extensively. In recent years, with the support of projects on resources survey, five concentrated areas have been discovered, and the primary reserve is about 1.5Mt.
立项依据 Northwestern margin of Tarim basin-(southwest Tianshan) Huoshibulake lead-zinc metallogenic belt Huosibulake Pb-Zn deposit Baishibulake Pb-Zn deposit Kada Pb-Zn deposit Kangxi Pb-Zn deposit Qiongkuer Pb-Zn deposit Shalitashi Pb-Zn deposit Tuiopa Pb-Zn deposit Wulagen Pb-Zn deposit
The Pb-Zn resources base in the western margin of Tarim basin The ore concentrating area in west margin of Tarim basin include: Wulagen Pb-Zn metallogenic belt in the basin formed in Mesozoic-Cenozoic; Kusilapu MVT Pb-Zn metallogenic belt in the southwestern margin of Tarim basin; Huoshibulake SEDEX Pb-Zn metallogenic belt in southwestern of Tianshan. formed in Devonian The western margin of Tarim basin will become the important Pb-Zn resource base with huge prospecting potential (>10Mt).
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