Xishimen iron mine located approximately 0.2km west of the mine in Wu'an Town Shimen Village, built in the late 20th century, 60 generations, the early 1970s, nearly one hundred million tons of proven reserves [1]. According to different thickness of the ore body, the sublevel caving method and the room and column method were used for mining, and the mining height was 40m. In order to further guide mining and production prospecting work in the mining area, this study takes Fe1# ore body as an example to analyze the mathematical characterization parameters and geological characteristics of the ore body during the exploration and mining stages.
1 ore body mathematical characterization parameters
1.1 Variation coefficient The variation coefficient of the Fe1# ore body exploration stage is shown in Table 1. It can be seen from Table 1 that the Fe1# ore body has a relatively uniform grade distribution, a relatively stable thickness, and a moderate change in area, with a coefficient of variation of 50% to 100%, regardless of the exploration stage or the mining stage.
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1.2 Two-level difference change index The calculation results of the Fe1# ore body second-order difference change index are shown in Table 2. It can be seen from Table 2 that the index value of the ore body change at the level of -40, 40, 80m is 10% to 40%, and the degree of change is small; the index value of the 0m level ore body grade change is 50% to 110%, indicating the ore body grade. The degree of change is greater.
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1.3 Mineralization rate The ore-bearing rate is an important indicator to measure the continuous degree of mineralization of ore bodies. In this study, the level of 0, 40, 80, 120m of the 25#~28# line of the mining area is selected for statistical calculation. The results show that: 1 the ore-bearing rates of different elevations in the exploration stage are 51.2%, 41.8%, 82.1%, 60.2%, 64.7%, and the ore ratio of Fe1# ore body is 64.7%; 60.7%, 43.7%, 67.9%, 67.3%, 62.5%, and the total ore ratio is 62.5%. In the exploration and mining stage, the ore content of the Fe1# ore body is 40% to 70%, and the part of the ore body that meets the requirements of the industrial ore body is slightly larger than the section that does not meet the industrial requirements.
1.4 Mineralization intensity index Take the 5# line of the mining area as an example, and divide the surface into six sections of 240m, 200-240m, 160-200m, 120-160m, 80-120m, 40-80m, according to the length and TFe Grade weighted single engineering grade and interval section grade. The calculations show that the mineralization intensity indexes in the exploration stage are 1.26, 1.13, 1.19, 0.80, 1.06, and 0.98, respectively. The mineralization strength indexes in the mining stage are 1.27, 1.14, 1.06, 0.87, 1.07, and 0.98, respectively. It can be seen that the mineralization intensity index of the ore body in the exploration stage and the mining stage is similar, and the change trend is the same. The mineralization strength of the 160-240m horizontal ore body is higher than 40-160m, which is basically consistent with the calculation result of the ore-bearing coefficient. According to the analysis, the upper stratum near the surface has the lava structure, pressure and temperature conditions formed by the ore body. Therefore, both the mineralization strength and the ore-bearing coefficient are higher than the lower ore body.
1.5 Ore body boundary modulus The ore body boundary modulus reflects the complexity of the ore body shape to a certain extent. The smaller the modulus, the more complex the shape. Conversely, the ore body shape is simple. In this study, we selected MapGIS6.7 software in the middle of the 0, 40, 80, and 120 m horizontal sections of the mining area and combined the ore body plan of different sections to calculate the boundary modulus of the ore body. The results show that the boundary modulus of the ore body in the exploration stage is 0.56, 0.80, 1.35, and 0.71, respectively. The boundary modulus of the ore body in the mining stage is 0.88, 0.89, 0.56, and 0.53, respectively. The total boundary modulus of Fe1# ore body takes the average of the above four horizontal boundary modulus, and the calculated results are about 0.86 and 0.72, respectively. It can be seen that the change of the boundary shape of Fe1# ore body in exploration stage and mining stage is relatively simple. After calculation, the grade change coefficient of Fe1# ore body is 17.41%～19.07%, the thickness variation coefficient is 82.98%～85.57%, the area variation coefficient is 59.02%～60.93%, and the total ore-bearing coefficient is 62.5%～64.7%. The boundary modulus is 0.72~0.86, which indicates that the grade of the ore body changes uniformly, the thickness changes are stable, the area morphology changes moderately, the boundary shape changes simply, and the comprehensive index of ore body shape complexity is medium.
2 ore body geological characteristics
2.1 Grade The Fe1# ore body grade mining is homogeneous in both stages. The average grade of the ore body is reduced from 43.26% to 41.98%, and the grade error rate is 3.05%. The grade error rate of different levels of resource reserves is also different. The proven resource reserve grade error rate is 0.64%, the controlled resource reserve grade error rate is 1.18%, and the inferred resource reserve grade error rate is 39.29%. During the exploration phase, the total reserves of Fe1# ore body meet the ≤20% reserve error standard requirement, in which the proven and controlled resource reserves can reach the storage error standard of ≤20%, and the inferred resource reserves partially reach ≤40% of the reserve error. standard requirement. It is shown that the amount of engineering control of the proven and controlled resource reserves of the Fe1# ore body during the exploration phase is sufficient, and the inferred resource reserves need to be controlled by the encryption project.
2.2 Thickness The thickness of Fe1# ore body is relatively stable in the exploration stage and the mining stage. The average thickness of the ore body is reduced from 15.13m in the exploration stage to 12.68m, and the ore body thickness error rate is 19.32%. The proved resource reserve thickness error rate is 12.58%, the controlled resource reserve thickness error rate is 11.21%, and the inferred resource reserve thickness error rate is 20.75%. According to the analysis, the thickness error rate of the proven, controlled and inferred Fe1# ore body is small, which can achieve the purpose of controlling the ore body.
2.3 Area After calculation, the area overlap ratio, shape æ­ª curvature and area error rate of Fe1# ore body are 66.95%, 61.52% and 13.62%, respectively. The Fe1# ore body is a medium-thick layer ore body. According to the general reference index (Table 3), the control of the ore body area in the exploration stage is reasonable (Fig. 1).
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2.4 Resource Reserves

This study selects the mining area -18#~37# line for comparative analysis of resource reserves. The results show that the exploration period of proven resource reserves is 48,377.9 thousand tons, the mining stage is 48,908,400 tons, the reduction is 279,500 tons, and the error is 0.58%. The exploration period of resource reserves is 2,506,800 tons, the mining stage is 30,647.3 thousand tons, an increase of 5,853,500 tons, the error is 18.22%; the inferred resource reserves exploration stage is 21,124,600 tons, and the mining stage is 1,76,572 tons, a decrease of 3,467,400 tons. The error is 19.64%. Further analysis shows that the proven, controlled or inferred resource reserves of the Fe1# ore body in the exploration stage can reach an error rate of ≤30%, indicating that the control level of the ore body resource reserves is sufficient in the exploration stage of the Xishimen iron ore mine.
3 types of exploration, exploration methods and engineering spacing
3.1 Exploration type, exploration method Exploration stage According to the geological characteristics of the ore body, the Xishimen iron ore deposit is large in scale, the ore body shape is moderate in complexity, the structure complexity is moderate, and the grade distribution is uniform. Therefore, it is determined that the mine belongs to the type II exploration type. (medium type). Except for the exploration method, except for the part of the exposed area in the northern area, which is controlled by a small amount of mountain engineering, all Other drilling engineering controls the ore body. The proven resource reserves are calculated according to the engineering spacing of 100m×100m, and the controlled resource reserves are calculated according to the engineering spacing of 200m×200m. The extrapolation of the C-level block segment or the extrapolation of the mine project is the inferred resource reserve. The type of survey is still determined as the Type II survey (medium type) during the mining phase. The exploration method in the mining stage controls the ore body by tunnel drilling combined with the mining roadway; the engineering spacing is consistent with the exploration stage, and the proved resource reserves are calculated according to the engineering spacing of 100m×100m, and the controlled resource reserves are calculated according to the engineering spacing of 200m×200m. . The extrapolation of the C1 block segment or the extrapolation of the seeing project is the inferred resource reserve.
The exploration stage and the mining stage of the Xishimen Iron Mine belong to the Type II exploration type (medium type), indicating that the type of ore body exploration determined in the exploration stage is more reasonable. In the exploration stage, a small amount of trenching engineering is used to control the surface of the northern area. The deep underground ore body is mainly controlled by drilling engineering. The exploration method using drilling + troughing in the exploration stage is in line with the ore geological conditions, and the mining stage adopts pit exploration + Drilling exploration methods are also in line with mine production prospecting requirements.
3.2 The engineering spacing is calculated. When the engineering spacing is 100m×100m, 200m×200m, 400m×200m, the calculated resource reserves errors in the exploration and mining phases are 0.58%, 18.22%, 19.64%, respectively, and both meet ≤20. % error standard; thickness error is 12.58%, 11.21%, 20.75%, nearly 20% error standard; ore body grade error corresponding to engineering spacing of 100m×100m, 200m×200m (0.54%, 1.18%) Both can meet the error standard of ≤20%, and the error is small. The ore body error corresponding to the engineering spacing of 400m×200m is 39.29%, which fails to meet the error standard, and needs attention in practical work.
3.3Mircomine ore body model In the 3D view state of the Mircomine software, the ore body interpretation line of each exploration line profile is first entered, and then a wireframe is created one by one between the adjacent two ore body interpretation lines, and finally the lines are created. The frames are connected and the ore body model of the exploration stage can be generated after verification (Fig. 2) [2-4]. It is calculated that the estimated reserves of Fe1# ore body using the Micromine software during the exploration phase are 93,731,700 tons, and the mining stage is 94,711,100 tons. The estimated resource reserves of the original exploration report are 94,485,500 tons, and the actual reserves of resources (964.035 million tons). Compared with the error reserves estimated by Micromine software, the error of the resource reserves is ≤10%, which indicates that the control of the resource reserves in the exploration stage of the Xishimen Iron Mine is sufficient. According to the comprehensive analysis, the exploration cost (B grade / 331) resource reserves are estimated by the engineering spacing of 100m × 100m in the exploration stage, and the (C1 grade / 332) resource reserves are correct using the engineering spacing of 200m × 200m. of.

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4 Conclusion

Taking the Fe1# ore body of Xishimen Iron Mine as an example, combined with the relevant calculation parameters and geological data, a detailed analysis of the exploration and mining was carried out. The analysis showed that the ore body of the Xishimen Iron Mine changed uniformly, the thickness changed more stably, and the area morphology changed moderately. The boundary shape change is simple, and the comprehensive index of ore body shape complexity is medium-sized. The exploration type determined during the exploration stage, the selected exploration means, and the planned engineering spacing are basically correct.

References [1] Yan Jiandong, Yan Jianheng, Xu Hua, et al. Design and implementation of safety hazard assessment system for Xishimen Iron Mine [J]. Modern Mining, 2015 (6): 143-144.
[2] Li Shouyi, Ye Songqing. Mineral Exploration [M]. Beijing: Geological Publishing House, 1997.
[3] Li Peng, Zou Xiaowei, Li Zhi. Reserves a copper deposit Micromine software-based estimation [J]. Modern Mining, 2016 (7): 193-195.
[4] Li Chunzhang, Du Dengfeng, Song Cubic, et al. Micromine software application shihu gold ore comparative analysis [J] exploration and mining. Modern Mining, 2016(6): 32-34
Article source: Modern Mining, 2011.5
Author: Wang Hong, Du Dengfeng, Li Junying, Li Yanli; Hebei Geological and Mineral Bureau Brigade eleventh Niu Jun new; Xishimen iron ore Copyright:

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