Comprehensive Exploration of Vein Molybdenum Deposit in Jidanping Formation in the South of Songxian County

Wang Wenda, Liu Guoying City, Zhao Jinzhou

(No.5 Geological Brigade of Henan Nonferrous Metals Bureau of Geology and Mineral Resources)

Comprehensive exploration of 1. vein molybdenum deposit and its significance

Comprehensive exploration refers to the exploration of deposits of the same metallogenic series located in the same metallogenic region or metallogenic belt according to the geological law of deposit formation, including the comprehensive exploration of different minerals in the same ore field (layer) and the overall evaluation of different sections of the same mineral.

The traditional meaning of vein-type molybdenum ore refers to molybdenum ore bodies composed of a single time-dependent pulse, or a time-dependent pulse and its ore-bearing altered zones on its upper and lower walls, or a molybdenum ore body composed of altered rocks (zones). The vein molybdenum deposit of Jidanping Formation in the south of Songxian County is a combination of the above three types.

In recent years, with the improvement of exploration and comprehensive research on gently inclined vein molybdenum deposits in Jidanping Formation of Xiong 'er Group in Southern Song Dynasty, it is found that there are also molybdenum deposits in the rhyolite porphyry of Jidanping Formation, which are characterized by: the surrounding rock is rhyolite porphyry; Mineralization is mainly molybdenite, which is distributed in the form of thin film or disseminated in the form of fine particles along the fault surface. Microscopically, molybdenite is 0.06 mm× (0.08 ~ 0. 18) mm in size, mostly flaky and irregular, and sometimes flaky aggregates are layered along ore fractures. Alteration is mainly potassium and silicification. Potassium alteration is characterized by porphyritic potash feldspar and pink rocks, while silicification is characterized by timely veinlets and reticulation, and the width is about 1 to several millimeters. The vein-type molybdenum deposit of Jidanping Formation in the south of Songxian described in this paper is a synthesis of the above three types, which is of practical significance to the comprehensive exploration of vein-type molybdenum deposits in this area.

2. Division of molybdenum metallogenic belt in East Qinling (Henan section)

According to the distribution characteristics of molybdenum deposits (spots) and molybdenum anomalies in East Qinling (Henan section), the molybdenum metallogenic belt in this area is divided as follows:

The molybdenum deposits in East Qinling (Henan section) can be divided into two metallogenic sub-zones: the molybdenum ore-forming sub-zone in the southern margin of North China platform and the molybdenum ore-forming sub-zone in North Qinling; Then the sub-zone of 20% mine is subdivided into five metallogenic concentration areas, and the northern zone is divided into Lingbao-Lushi metallogenic concentration area, Songxian-Luanchuan metallogenic concentration area and Fangcheng Silidian-Guaihe metallogenic concentration area from west to east. The southern belt is divided into Xixia Zhaigen-Erlangping metallogenic concentration area and Zhenping Qiu Shu Bay metallogenic concentration area from west to east. The whole vein molybdenum exploration area is located in Songxian-Luanchuan metallogenic concentration area (Ⅰ 2) (Ⅰ 2-2) (Figure 1).

Vein molybdenum deposits of the Jidanping Formation in the south of Songxian County are mainly distributed in the Waiweishan fault uplift area of Taiyuan sag in Hua Xiong on the southern margin of North China platform. The stratum is mainly Jidanping Formation of Xiong 'er Group, and the lithology is mainly rhyolitic porphyry. Geographical location starts from Songxian County in the north and reaches the northern boundary of Heyu rock body in the south, that is, Yuchiling-Huangyupo-Daqiaogou in the north; From Dazhangzhang in the west to Barnyard in the east, the area is about 560km2 (Figure 2).

Thirdly, the opportunity and basis for comprehensive exploration of vein-type molybdenum deposits.

(1) Timing of comprehensive exploration of vein-type molybdenum deposits

On April 20th, 2009, Henan Provincial Department of Land and Resources held a symposium on mineral resources exploration and development management and mobilization and deployment of geological prospecting reform and development in the whole province in Golden Hotel, which set off a big discussion on geological prospecting reform and development in the whole province. On May 20th, a symposium hosted by Henan Provincial Department of Land and Resources and undertaken by Henan Provincial Bureau of Geology and Mineral Exploration and Development was held in Crowne Plaza Zhongzhou Hotel, Henan Province. Specially invited academicians, academicians, Pei and Zhao of China Academy of Sciences, as well as famous domestic geologists and deposit scientists Wang Ruijiang and Mao Jingwen. Leaders at all levels and geologists from the geological and mineral system of Henan Province attended the meeting, demanding that everyone further emancipate their minds, change their concepts, persist in developing and expanding the main business of geology and mineral resources, rely on scientific and technological innovation, implement comprehensive exploration, and achieve a major breakthrough in prospecting.

Figure 1 Distribution of molybdenum deposit types and division of metallogenic belts in East Qinling (Henan section)

Geological schematic diagram of vein molybdenum deposit of Jidanping Formation in southern Songxian County.

(II) Basis for comprehensive exploration of vein-type molybdenum deposits

1. Our bureau has many mining rights.

At present, Henan Nonferrous Metals Bureau of Geology and Mineral Resources has many prospecting rights in Songxian County, and there are five registered mining rights in the stratum of Jidanping Formation in the south of Songxian County. The Fifth Geological Brigade of Henan Nonferrous Metals Geology and Mineral Resources Bureau owns three mining rights: molybdenum general survey in Daxigou mining area of Songxian county (area 4.27km2), molybdenum detailed survey in Zhifang mining area of Songxian county (area 5.69km2) and lead mine detailed survey in Tuling village of Songxian county (area 7. 1km2). The second geological brigade of Henan Nonferrous Metals Geology and Mineral Resources Bureau owns 1 mining right, namely "molybdenum survey in Maogou mining area of Songxian county" (area 8.89km2); Henan General Institute of Nonferrous Metals Geological Exploration owns the mining right of 1, namely "Detailed Survey of Lead Ore in Fantaigou Mining Area of Songxian County" (with an area of 4.62km2). It should be noted that although some mineral rights have been transferred to others or other companies, and some mineral rights were lead-zinc deposits at the time of registration, their essence is vein-type molybdenum deposits. Some submitted detailed molybdenum investigation reports in social service projects, and preliminarily estimated the submitted cumulative molybdenum resources (332)+(333)+(334)? 30 thousand to 50 thousand t

2. Rich experience in vein molybdenum exploration and comprehensive research.

The discovery of the vein molybdenum deposit in the Jidanping Formation in the south of Songxian County began in 2005. During the general survey of Zhifang Molybdenum Mine in Songxian County, the Fifth Geological Brigade of Henan Nonferrous Metals Bureau of Geology and Mineral Resources found six large molybdenum veins in the range of 5.69km2, all of which occurred in Jidanping Formation, and the output was slow. The length is 200 ~ 2800 m, the thickness is 0.39 ~ 10.86 m, the inclined depth is 80 ~ 550 m, and the coefficient of variation of thickness is 60% ~ 100%, which is relatively stable. The shape of ore body is vein-like, lenticular and irregular cystic, with branching compound, expansion and contraction in some areas. The ore grade is 0.07 1% ~ 0. 158%, and the coefficient of variation is 50% ~ 100%, which is relatively stable. The occurrence of the vein changes greatly, and the whole vein tends to the northeast, with the occurrence of 10 ~ 8 1 ∠ 8 ~ 55 and the dip angle of 15 ~ 2 1, which tends to the northwest.

The ore body in the upper part of the pulse-type molybdenum mine is relatively complete and the mineralization is weak. The lower vein is broken, joints are developed, and it is smoky gray with strong mineralization. Molybdenite has a fine grain size of 0.06 mm× (0.08 ~ 0. 18) mm, which is indistinguishable with naked eyes and constitutes the upper part of the ore body. In the footwall (upper) of the timely vein, shear zone molybdenum ore bodies appear locally, with high mineralization degree. Molybdenum deposits are often distributed in the form of belts, veinlets or disseminated, and form ore bodies with * * * at the lower part of the corresponding pulse. The thickness changes greatly, and most of them occur in the footwall of the corresponding pulse in the form of small lenses.

According to the identification of rocks and minerals, the main metal minerals in the ore are pyrite and molybdenite, followed by chalcopyrite, galena, sphalerite, scheelite and wolframite. Gangue minerals mainly include quartz and potash feldspar, followed by fluorite, dolomite and calcite.

Ore texture includes authigenic-allotypic granular texture, irregular texture, assemblage, inclusion texture, metasomatic residual texture, secondary allotypic granular texture, residual porphyritic texture and so on. Ore structures include massive structures, banded structures, star-shaped (disseminated) structures and reticulated vein structures.

The surrounding rock of vein is rhyolitic porphyry, and along the interface between the upper and lower walls of the corresponding vein, there are generally potassium and silicification alterations, and the potassium alteration becomes light red and fleshy red, mostly linear or banded; The intensity of alteration is related to the thickness of the corresponding vein. The larger and closer the vein is, the larger the alteration range of surrounding rock is. The narrower the vein, the smaller the alteration range, showing linear or banded alteration, and gradually weakening to both sides.

The enrichment law of molybdenum mineralization: the stronger the potassium and silicification alteration of surrounding rock, the wider the alteration range and the stronger the corresponding molybdenum mineralization, and the molybdenum mineralization is positively correlated with the alteration intensity of surrounding rock; Due to tectonic movement, the shear deformation and interlayer sliding of the timely vein and the surrounding rock of the footwall produce a large number of interlayer cracks, which often form banded, veinlets or disseminated ore-rich bodies. The mineralization of the timely vein is uneven, the upper part of the timely vein is relatively complete and the mineralization is relatively weak. The ore in the lower part of the time pulse and the contact zone with surrounding rock is broken and mineralized strongly. Generally, it is banded, veined or compound veined ore, and molybdenum mineralization is the strongest; Molybdenum mineralization is better in the part where the occurrence of vein changes greatly.

Through the general survey of Zhifang molybdenum mine area in Songxian county, the ore-controlling conditions, mineralization enrichment law and ore quality characteristics of vein molybdenum mines in the south of Songxian county are basically found out. Submit (332)+(333)+(334)? The molybdenum resource is about 3000t, and it is predicted that (333)+(334) can be obtained. The molybdenum resource is about 10000 t.

3. Scientific and technological innovation projects provide technical support for molybdenum exploration.

Through the scientific and technological innovation project of Henan Nonferrous Metals Bureau of Geology and Mineral Resources in 2006 —— "Study on molybdenum exploration area in East Qinling (Henan section)" and the scientific and technological innovation project of Henan Province in 2008 —— "Types and evaluation criteria of molybdenum deposits in East Qinling", the evaluation of vein molybdenum deposits in this area has been further improved, and the comprehensive research level has also been greatly improved.

The rhyolite porphyry of Jidanping Formation in Xiong 'er Group is rich in W, Mo, Pb, Zn, Au and Ag, but the volcanic rocks in Xiong 'er Group have dense rock structure and poor permeability. Vein molybdenum deposits in this area are probably hydrothermal filling deposits after Xiong 'er volcanic period, and their mineralization is closely related to volcanic mechanism and faults during volcanic activity.

4. Great progress has been made in the general survey of Daxigou vein-type molybdenum deposits in Songxian County.

According to the Notice of Henan Provincial Department of Land and Resources on Issuing the Task Book of Provincial Geological Exploration Fund (Working Capital) in 2008, the "General Survey of Daxigou Molybdenum Mine in Songxian County, Henan Province" was listed as a continuation project of the provincial geological exploration fund (Working Capital) in 2008, which was undertaken by the Fifth Geological Brigade of Henan Nonferrous Metals Bureau of Geology and Minerals.

Through the general survey of daxigou molybdenum mine, the surface veins in the middle and deep parts were traced, exposed and controlled. It is found that molybdenum veins exist not only in the shallow part, especially in the construction of ZK0708 drilling project, but also in the deep part, which is of far-reaching significance to guide the exploration of vein-type molybdenum deposits in this area.

ZK0708 footage is 600.59m, see 7 layers of mine. Lithology is rhyolite porphyry, gray and light red, with developed joints and fissures. Most of them are filled with reticular veins, and pyrite and molybdenite are disseminated. The first layer vein hole depth is 247.95 ~ 25 1.25m, thickness is 3.30m, and grade is 0.088%. The second layer vein hole depth is 422.07 ~ 423.6438+0 1m, thickness is 1.04m, and grade is 0.044%. The vein hole depth of the third layer is 431.19 ~ 433.19m, the thickness is 2.00m, and the grade is 0.032%. The fourth layer vein hole is 45 1.03 ~ 458.83 m deep, 7.80m thick and 0.054% in grade. The fifth vein is 494.3 1 ~ 496.26 meters deep and 1.95 meters thick, with a grade of 0.055%. The sixth pulse is 556.67 ~ 558.67 meters deep and 2.00 meters thick, with a grade of 0. 12 1%. The seventh vein is 588.73 ~ 592.73 meters deep and 4.00 meters thick, with a grade of 0.067%. The construction of ZK0708 drilling project points out the direction of molybdenum exploration in this area and lays the foundation for deep prospecting.

According to the current geological survey progress, it is expected to submit (333)+(334)? The molybdenum-like resources are about 20 ~ 30 thousand t, and a medium-sized molybdenum deposit can be obtained.

Four. Guiding ideology and work arrangement of comprehensive exploration of vein molybdenum deposits

Guiding ideology for comprehensive exploration of vein-type molybdenum deposits in the southern part of Songxian County: With Henan Nonferrous Metals Bureau of Geology and Mineral Resources as the main body, unified planning and comprehensive exploration should be carried out according to the ownership of mining rights and the exploration degree of vein-type molybdenum deposits.

Principles of work deployment: from known to unknown, from outside to inside, from shallow to deep, from sparse to dense. Carry out comprehensive research and metallogenic prediction on the surface, focus on dissecting known deposits, and guide the comprehensive exploration of molybdenum deposits in this area.

According to the existing mining rights and geological achievements of vein-type molybdenum exploration, exploration research and molybdenum exploration in different horizons were carried out in Jidanping Formation of Xiong 'er Group in the southern margin of North China platform and Waifangshan fault uplift area in Taiyuan Depression, Hua Xiong. First, carry out comprehensive research on vein molybdenum deposits and1∶ 50,000 metallogenic prediction in the range of about 560km2, and narrow the prospecting target area; Secondly, carry out 1 ∶ 25000 pulse survey and molybdenum anomaly verification in the favorable metallogenic area of pulse-type molybdenum deposits, and delineate the prediction area; Third, through further geological pre-investigation, trace, expose and verify the surface vein through a few projects, and delineate the investigation area; Fourthly, through the exposure of surface dredging exploration project and the control of medium-deep drilling project, the key sections and concentrated areas of molybdenum veins are surveyed, and finally the potential of vein-type molybdenum resources in this area is evaluated, and the corresponding molybdenum resources are submitted to provide molybdenum resources guarantee for local economic development.

Verb (abbreviation of verb) Evaluation of comprehensive exploration resources potential of vein molybdenum mine

In recent years, our bureau has carried out vein molybdenum exploration in Jidanping Formation in the south of Songxian County, with five exploration certificates, with an exploration area of 30.57km2 It is preliminarily estimated that the accumulated molybdenum resources submitted are (332)+(333)+(334)? 30 thousand to 50 thousand t

The Jidanping Formation of Xiong 'er Group is widely distributed in Waifangshan area in the south of Songxian County, covering an area of about 560km2. Nearly 10 vein molybdenum deposits have been discovered, of which 3 are expected to reach medium scale. At present, there are 5 vein molybdenum deposits with a total exploration area of 30.57km2, and there is a huge exploration space for molybdenum deposits in this area. Through preliminary metallogenic prediction, the potential of vein molybdenum resources in this area can reach 200,000 ~ 300,000 tons.

Conclusion of intransitive verbs

Vein molybdenum deposits of Jidanping Formation in the south of Songxian County are mainly distributed in Waiweishan fault uplift area in Taiyuan Depression, Hua Xiong, and the stratum is Jidanping Formation of Xiong 'er Group. There are a large number of gently inclined vein molybdenum deposits in this area, and there is huge exploration space for molybdenum deposits. We must take advantage of the east wind of the discussion on the reform and development of geological prospecting to promote the comprehensive exploration of vein-type molybdenum deposits, strengthen the deep prospecting and achieve a major breakthrough in geological prospecting.