(15) Physical and Geological Data of Dataigou Iron Mine in Liaoning Province

Dataigou Iron Mine in Liaoning Province, located in Qiaotou Town, Benxi City, is the largest Anshan-type iron deposit discovered in recent years. The deposit is a concealed super-large iron deposit with a buried depth of1100 ~1200m. The controlled ore body extends for 2000m, the maximum extension is 840m, and the widest part is 1 100 m, which is a single ore body with nearly vertical thick plates and few inclusions. Ore types include magnetite quartzite (magnetite), hematite quartzite (hematite) and its transitional magnetite hematite quartzite (mixed ore). The ore content is uniform, and the content of harmful impurities in the deposit is low. It is preliminarily estimated that the resources of 333+332 are about 34× 108t. The timely collection and arrangement of physical geological data of Dataigou Iron Mine not only shows its metallogenic geological characteristics and work achievements, but also provides physical data services for future geological prospecting and scientific research.

1. Mining Geology

(1) tectonic background

Anshan-Benxi area is located in the eastern part of the northern margin of North China landmass, belonging to Taizihe-Hunjiang platform depression in Jiaoliaotai, and the fourth structural unit is Liaoyang-Benxi depression. Dataigou iron ore district is located in the Anshan-Benxi iron ore metallogenic belt, at the southwest end of the NeoArchean Anshan-Benxi volcanic sedimentary basin. There are iron-bearing deposits in cherry orchard Formation and Dayugou Formation in this area, which are the largest Anshan-type iron deposits and the largest resources, and are also the concentration areas of super-large and large iron deposits in China.

(2) mining strata

The strata exposed in the mining area are mainly Neoproterozoic Xihe Group Diaoyutai Formation, Nanfen Formation and Qiaotou Formation, Sinian Konka Formation, Cambrian Jianchang Formation and Shantou Formation. The iron-bearing rock series of Archean Anshan Group is not exposed on the surface, and the iron-bearing rock series and the top of the ore body are buried below the surface1100 ~1200m. Among them, cherry orchard Formation of Anshan Group is the most favorable ore-bearing strata in this area, including banded magnetite quartzite, hematite quartzite, hematite magnetite quartzite and chlorite schist.

(3) Mining area structure

Dataigou iron ore district is located in the east of Anshan-Benxi iron ore metallogenic belt. Nanfen Iron Mine 10km in the south, Gongchangling Iron Mine 20km in the west, Sishanling Iron Mine 10km in the east and Beitai Iron Mine 10km in the north. There is a large area of sedimentary caprock on the surface of the mining area, with simple geological structure and undeveloped fault structure. There is a NE-trending Taigou fault in the south of the mining area.

(4) Magmatic rocks

Magmatic rocks are not developed in the area, and no rock mass is exposed on the surface; Only sporadic diorite porphyrite veins are seen on a small scale. The rocks seen in the borehole are mainly Archean granite, diorite vein, diorite porphyrite vein and chronological vein.

(5) Magnetic anomaly

The scale of aeromagnetic anomaly in Dataigou is large, and the anomaly center is obvious, and the anomaly center Δ δt > 4000 nt. The high-precision magnetic survey in the ground 1∶ 10000 area delineated the magnetic anomaly of Dataigou in detail. The plane isoline of δ T anomaly shows that the anomaly shape is oval, which runs northwest and from southeast to northwest, and the anomaly gradually narrows in pear shape, and the highest anomaly value of δ T is 5990nT；; Bounded by 1000nT isoline, the major axis is about 8km, and the widest part of the minor axis (anomaly center) is about 4 km; With 1500nT isoline as the boundary, its major axis is about 4.8km, and its minor axis is about 3.5km, and the ratio of major axis to minor axis is 7∶5. From the high magnetic profile, the curve is symmetrical and there is almost no negative value, which indicates that the ore body has a large extension range and the bedding magnetization is relatively uniform. Through quantitative calculation, it is inferred that the average buried depth and width of the ore body are 1 103m and 1029m, respectively, and the length of the ore body is more than 5km.

2. Geology of mineral deposits

(1) ore body characteristics

The data of 20 boreholes in five exploration lines (exploration lines 0, 3, 4, 7,15) in the mining area show that the ore body is generally thick plate-shaped, with a slight dip to the northwest and a steep dip to the southwest. The ore body gradually narrows and inclines to the northwest. The five exploration lines control the strike length of the ore body to be 2000 m (the ore body still extends to the northwest, but it is temporarily out of control), the zero exploration line passes through the center of magnetic anomaly, the widest point of the ore body is 1 100m, the narrowest point is 650 m (four exploration lines), and the maximum extension depth of the ore body is 840m m ... The ore body is mainly composed of banded iron-bearing quartzite, and. Ore types mainly include: banded magnetite hematite (mixed ore), banded hematite quartzite, banded magnetite quartzite; Most of them are banded magnetite hematite quartzite, accounting for about 2/3 of the total ore.

The upper part of the ore body is banded or breccia hematite (red ore), the middle part is magnetite hematite (mixed ore), and the lower part is mostly magnetite (magnetic ore), that is, magnetite gradually increases from the head to the deep part; It shows that the upper part of the ore body is strongly influenced by archaea and oxidation, and hematite has replaced magnetite to form hematite or mixed ore. The thickness of red ore varies in different parts of the ore body, and an uneven boundary is formed between red ore and mixed ore or magnetic ore in the ore body.

(2) Ore type and structure

The mineral assemblage in banded iron ore is relatively simple. Light and thin section studies show that iron ore contains more than 10 minerals, which belong to four categories, such as oxides, silicates, carbonates and sulfides, among which carbonate and sulfide minerals are very few.

The main structures of ore are mosaic granular metamorphic structure, scale granular metamorphic structure and columnar granular metamorphic structure. The ore structures are mainly banded structures and banded structures, but also flaky, massive, breccia and small fold structures.

3. Project progress and achievements

(1) Project Introduction

In 2006, Dataigou Iron Mine in Liaoning Province won the national land and resources survey project, and the project name was: Iron Mine Evaluation in Wujiatai-Liaoyang Sunjiaying Area, Anshan City, Liaoning Province. Through the verification of six aeromagnetic anomalies, including Dataigou, Huazi in Liaoyang, Shoushan-Tengao in Anshan, Gaotuozi-Tengao in Anshan, Zhujiatun-Anjiapuzi in Shenyang and Dahugou in Liaoyang, it was finally determined.

(2) Project deployment and physical workload

Since 2008, a total of 65,438+07 boreholes have been constructed on exploration lines 0, 3, 4, 7 and 65,438+05. The controlled ore body has been extended for 2000m, the widest part of the controlled ore body is 1 0,036,5438+0 m, and the deepest part of the controlled ore body is-1 0,770 m, which has not penetrated the ore body. The ore body generally strikes northwest, tends to southwest, and the dip angle is 85; The buried depth of the ore body is1100 ~1200m (elevation-1000 ~-900m), and the edge of the ore body has been basically controlled by drilling. The cumulative footage exceeds 3× 104m, and all iron ore bodies are seen. According to drilling hole 17 and five exploration lines (line spacing is 400m, and line 7 to 15 is 800m), it is preliminarily estimated that 2000m is used to control and infer (332+333) that iron ore resources exceed 30× 108t.

4. Present situation of mine core preservation

Since the evaluation project of Wujiatai-Sunjiaying Iron Mine in Anshan, Liaoning Province was started, a large number of cores have been produced. Due to the short time and the attention paid by geological prospecting units to these physical geological data, these cores are well preserved in the core library and neatly packed together in the order of drilling holes and box numbers. Various analytical samples and sub-samples produced are kept by Liaoning Institute of Geology and Mineral Resources, the exploration unit.

5. Screening and collection of physical geological data

All the boreholes in Dataigou iron mine area have seen iron ore bodies, but they have not penetrated the iron ore bodies, indicating that the iron ore bodies are huge in thickness and uniform in content. According to the drilling hole currently under construction, the strike length of the ore body is controlled to be 1200m, and the horizontal width of the ore body can reach 1036m. No matter the strike or dip, it is not controlled by the ore body boundary. According to the thickness and scope of iron ore, it is estimated that the total amount of iron ore resources controlled and inferred over 2000m will exceed 30× 108t, which will become the largest iron ore resources in China and even the world. According to the magnetic anomaly, the length, width and extension of the ore body can reach 1440m, 1029m and 1500m, respectively, and the predicted prospective resource is 76.05438+0× 108 t, which is the largest single iron ore in the world at present.

ZK30 1 borehole with a depth of 20 15.77 m has a good prospecting prospect. From the hole depth 1745.05 ~ 20 15.77 m, we can see five layers of banded hematite quartzite, grayish white steel gray, granulite structure and banded structure. The black band is mainly composed of hematite and specularite, with a small amount of chronology. Rock has no magnetism. It contains a small amount of magnetite locally, and its magnetism is weak. Hematite, steel gray, reddish brown, irregular particles. The average TFe content in the whole mining area is 29.34%, and the TFe content reaches 37.85% at the hole depth 1865.84 ~ 1869.84 m; The TFe content reached 30.44% at the final pore depth of 2012.98 ~ 2015.77 m.

6. Relevant information

1) Overview of Dataigou Iron Mine in Benxi, Liaoning Province;

2) Geological map of Qiaotou Iron Mine;

3)ZK30 1 histogram;

4)3 Profile of exploration line.