4.7. 1 Q8 pulse
4.7. 1. 1 shape of ore-bearing fault plane
Using the database established by the exploration data taken from vein Q8, after preprocessing the data, taking (x', z, y') data, that is, the observed value of vein strike x' as the abscissa, z (elevation) as the ordinate, and the coordinate of the lower fracture segment y' as the observed value, the trend analysis of 1 time is carried out, and the isoline of 1 time trend residual value is carried out.
Fig. 4.39 12 joint plan of different elevation fractures in vein.
Fig. 4.40 Q 12 Joint Plan of Metal Quantity Distribution in Different Elevation Profiles of Pulses (Coordinate Correction)
Fig. 4.4 1.8 contour map of the shape of ore-bearing fault plane (main trend residual)
4.7. 1.2 Spatial simulation of ore-hosting faults (ore storage)
The development degree and scale of ore bodies (veins) in ore-hosting fault structures depend on the size of expansion space (ore storage space) in ore-hosting fault structures. The existing data (our experience in other mining areas in Xiaoqinling) show that the fracture surface of the fracture zone of ore-hosting structure in this area is gentle and wavy, and the formation and distribution of ore storage space (expansion space) are mainly controlled by the fracture surface shape and the fracture activity mode during mineralization. In the following, the mathematical function is cited, and combined with the research results of kinematics and dynamics of Q8 vein hosting fault, the relationship between fault plane shape, fault activity and ore storage space of Q8 vein hosting fault is expounded, so as to make metallogenic prediction.
(1) waveform decomposition and synthesis
Using the established exploration engineering database, the abnormal data of the first trend of the fault plane (the lower segment of the fault) are obtained, and then according to these data, the waveform is decomposed by the designed computer program (according to Bai Wancheng, 20 10), and the results are listed in Table 4.6.
Table 4.6Decomposition Parameters of Lower Segment Waveform of No.8 Pulse Fault
Note: A in the table refers to the amplitude (m); L- wavelength (m); β wave propagation direction (clockwise in X direction is positive).
As can be seen from Table 4.6, the first, second and third order waves decomposed by Q8 pulse are the most effective. Among them, the amplitude and wavelength of the first-order wave are large, and the wave propagates in the direction of 109, and the axial direction is lateral to the direction of SE 19 (β is the propagation direction of the wave, perpendicular to the axial direction); The second-order wavelength is equivalent to the first-order wave, but the amplitude is slightly smaller than the first-order wave, and the axial direction is steep to SW, almost vertical; The third-order wavelength is also equivalent to the first-order wave, but the amplitude is smaller than that of the first-order wave, and the axial side is SW25. The amplitude of the first, second and third order waves is greater than other waves, and the sum of the amplitudes is 57.8 1m, so the superposition of the first, second and third order waves determines the basic shape of the fracture surface, that is, the spatial distribution of the peaks and valleys. Since the fourth wave, the amplitude has obviously decreased, which belongs to the second wave and only affects the local shape of the section. In addition, it can be seen that with the increase of wave order, the amplitude and wavelength decrease as a whole, so the secondary wave with amplitude less than the twelfth wavelength can't actually control the mineralization and enrichment, and it is of no practical significance to further decompose the waveform.
From the wave decomposition parameters, it is also found that the ore body or ore belt and ore body mainly have three directions, one is SE 19 direction, the other is 25 southwest direction, and the third is SW80 (nearly vertical). The theoretical basis of the above-mentioned spatial distribution law of ore bodies, especially the horizontal and orebody spacing and ore-free spacing law, is determined by the propagation direction, wavelength and amplitude of these third-order waves. The theoretical analysis is in good agreement with the actual exploration results.
After the waveform decomposition is completed, use the data in Table 4.6 and the waveform function to synthesize the waveform:
Exploration theory, technical method and prospecting demonstration of replacement resources of endangered gold deposits
The function values of the deep, eastern and western sections of the mining area are calculated respectively, and the vertical projection map, that is, the waveform prediction map of Q8 vein fault plane, is made. Comparing the simulation diagram of the known section (Figure 4.42) with the actual observation diagram of the section (Figure 4.4 1), it can be seen that the synthetic waveform diagram (simulated fracture morphology diagram) is in good agreement with the actual fracture morphology diagram, but there are some differences in local morphology. The secondary small peaks and valleys in the simulation diagram can not be well reproduced, and the fracture morphology can not be fully and truly reflected. This makes us realize that the prediction method is reliable in predicting the distribution position of ore veins (belts) at present, but it has some deviation in indicating the position of ore bodies. Therefore, using fault plane waveform simulation method and other prospecting methods (such as geochemical method and deposit geology method) to predict unknown areas can improve the reliability of location prediction.
Fig. 4.42 Prediction Diagram of Fracture Waveform of No.8 Pulse Control Section
(2) Spatial simulation of capacity expansion (ore storage)
The expansion space (ore storage space) should be the sum of the collapse space formed by the relative sliding of the upper and lower walls of the fault and the space generated by lateral displacement. According to Bai Wancheng's research (199 1, 1995), the expansion space can be expressed as:
In the ideal state of complete incompressibility of rock, the thickness of collapse space caused by relative sliding of cracks is d 1(x):
Exploration theory, technical method and prospecting demonstration of replacement resources of endangered gold deposits
Due to vertical uplift and horizontal lateral stretching, rocks often have wedge-shaped cracks, and the angle of cracks is very small, so its lateral displacement d2(x)=(l 1-x)sinβ.
Comprehensive available functions of extended space:
Exploration theory, technical method and prospecting demonstration of replacement resources of endangered gold deposits
Effective function of expansion space in the ideal state of complete compression of rock;
Exploration theory, technical method and prospecting demonstration of replacement resources of endangered gold deposits
To describe, as shown in figure 4.43, this area is a synthetic expansion space.
The geological significance of the parameters in the above expression is:
X is the downward direction of the upper plate; Y is the vertical direction in which the whole section appears; A is the amplitude of the waveform; L is the wavelength; A is the sliding displacement of the upper wall; L 1 is the maximum extension of fracture tendency; β is the degree of wedge fracture angle.
Fig. 4.43 Schematic diagram of the relationship between fracture surface waveform, relative displacement, lateral displacement and ore-hosting space.
In fact, the relative sliding of the upper and lower plates is very small, and the contact part (compression zone) of the two plates is neither completely incompressible nor completely compressible, but somewhere in between. As can be seen from the above function formula:
1) amplitude is directly proportional to the thickness of ore-bearing space and inversely proportional to the buried depth;
2) In a certain range (α < L/4), when the displacement is large, the thickness of ore-bearing space is also large;
3) Wavelength has the greatest influence on the continuity of ore-hosting space, which is basically proportional.
It is concluded that ore-hosting faults with large amplitude, large lateral displacement, large wavelength and large shear displacement (relative sliding of upper and lower walls) are easy to form large-scale expansion space, and only in this way can large-scale industrial ore bodies be formed.
Based on the synthetic data of fault waveforms, the possible active modes of Q8 vein-like ore-bearing faults are simulated mathematically. Figures 4.44-4.49 give the spatial distribution of possible extension by simulating normal fault slip, Zuo Zheng fault slip, right normal fault slip and thrust, right thrust and left thrust in fault-controlled sections respectively, and compare it with the spatial distribution (linear metal content) and profile morphological position of known ore sections. In the simulation diagram, the expansion space formed by normal fault sliding is most consistent with the distribution position of ore bodies, followed by the expansion space formed by right normal fault sliding. Some lean ore bodies are controlled by the expansion space formed by left thrust. The expansion space formed by other activities is quite different from the spatial distribution of ore bodies. It is consistent with the actual observation results.
From the analysis of the cross-section shape and spatial position of gold ore bodies, the main gold ore bodies are distributed in the lower left of the uplift area of the profile, followed by the lower right, and some are located in the upper right of the uplift area. The first two are mainly controlled by the expansion space formed by normal fault sliding and right-lateral characteristics; Located at the upper right of the uplift area, it is controlled by the expansion space formed by the left thrust of the fault. Because the second mineralization in this area is undeveloped, the thick Shi Ying vein located at the upper right of the uplift area is poorly mineralized.
Fig. 4.44 Simulates the spatial distribution of expansion when the known section of No.8 fault slides with all data.
Fig. 4.45 Simulates the spatial distribution of expansion when the right normal fault in the known section of No.8 fault slides with all data.
Fig. 4.46 Using all data to simulate the spatial distribution of expansion of Zuo Zheng fault in the known section of No.8 fault when it slides down.
Fig. 4.47 Simulates the spatial distribution of expansion when the known section of No.8 fault is thrust with all data.
Figure 4.48 Simulates the spatial distribution of expansion when the known section of No.8 fault is pushed to the right with all data.
4.7. 1.3 Prediction and evaluation of tectonic mineralization
As mentioned above, the occurrence position and mineralization intensity of gold ore bodies are closely related to the expansion space (ore storage space) formed by ore-hosting faults when the veins are in place during the metallogenic period. The spatial distribution and scale of ore-hosting faults are determined, and the possible formation position, law and mineralization intensity of gold bodies are basically found out. In other words, the scale and enrichment intensity of gold ore bodies are basically determined.
According to the above knowledge obtained in the known ore section, the conceptual model of blind ore prediction of Q8 vein is summarized as follows:
1) gold ore bodies are mainly distributed in the expansion space formed by normal slip of faults (right); Some lean ore bodies are distributed in the expansion space formed by the left thrust of the fault;
2) The main gold ore bodies are mostly located below the wavy uplift area of the profile, especially at the lower left, followed by the lower right, and some bad ore bodies are located at the upper right of the uplift area.
The mathematical model established by using Q8 pulse observation data has been simulated. The expansion space formed by normal fault sliding within the Q8 pulse coordinate range is 39,437,200-37,443,400 (the total length from east to west is 6200m), and the elevation range is 0- 1400m. Combined with the expansion space formed by early left thrust, the ore body is located and predicted (Figure 4.50).
Figure 4.49 Simulates the spatial distribution of expansion when the known section of No.8 fault is left thrust with all data.
As can be seen from the forecast diagram:
The main body of expansion space formed by normal fault sliding in 1) section is in the southeast wing, with a lateral dip angle of about 20, which is controlled by the first-order wave, and it is the dominant controlling factor for the emplacement of Q8 vein ore bodies and controls the distribution of ore belts. Within the predicted range, there are three parallel ore belts. At present, the main mining area is the upper ore body of the central ore belt.
2) From the expansion space of the ore belt, it is found that one direction is SW with a lateral angle of about 30, which is controlled by the second, third and fourth waves and controls the lateral direction of the main ore body.
3) The distance between the beaded ore bodies in the southwest is about 500m, and the theoretical distance between the main ore bodies in the southeast is about 500m, forming a rhombic distribution pattern.
On this basis, three key target areas (points) are predicted (Figure 4.50): The predicted Grade I target area is basically consistent with the structural ore-hosting space of the current ore-controlling area, and the predicted resources are large.
The coordinates of I- 1 target area are roughly: 37,438,500-37,439,400, with an elevation of 200-500 m, of which the middle part of 560 has been mined, but it is located in the east, and its deep part (especially in the west) still has great prospecting value.
The coordinates of I-2 target area are roughly: 37441200-37441800, with an altitude of 500-700 m; The upper part of the southeast wing of the target area is the current main mining area, and the upper part of the southwest wing has the original geological exploration area, both of which belong to known metallogenic areas, and the target area has great metallogenic advantages.
It should be pointed out that the scope of the predicted area delineated this time is the approximate scope of the whole mineralization, and as for the single ore body within this scope, it is also affected by the secondary waveform factors. That is to say, within the scope of the prediction area, there are still secondary enrichment laws of mineralization, which should be paid attention to.
Q 12 pulse
4.7.2. 1 shape of ore-bearing fracture surface
After preprocessing the data collected by pulse Q 12, rotate the NE direction to the EW direction, and take (x', z, y') data, that is, the X' coordinate of vein strike is the abscissa, the Z (elevation) is the ordinate, and the Y' coordinate of the lower fracture is the observed value, and then conduct 1 time trend analysis, and the remaining/KLOC.
Fig. 4.50 Q8 spatial simulation of ore-hosting and orebody location prediction diagram formed by normal fault sliding of vein (see text for numbering description in the diagram).
Fig. 4.5 1 Q 12 vertical and vertical projection of vein section shape.
Spatial simulation and blind ore prediction of ore-hosting faults in 4.7.2.2
(1) waveform decomposition and synthesis
The waveform decomposition results are shown in Table 4.7. As can be seen from Table 4.7, the first wave and the second wave of Q 12 pulse decomposition are the most effective. Among them, the first-order wave has the largest amplitude and larger wavelength, and the wave propagates along the direction of 132, and the axial direction is lateral to SE48 (β is the propagation direction of the wave, perpendicular to the axial direction); The second-order wavelength is equivalent to the first-order wave, but the amplitude is smaller than the first-order wave, and the axial direction is as steep as SW, and the lateral angle is about 60. The amplitudes of the first wave and the second wave are larger than those of other waves, and the sum of the amplitudes is 21.3m. Therefore, the superposition of the first wave and the second wave determines the basic shape of the fracture surface, that is, the spatial distribution of convex peaks and concave valleys. Starting from the third-order wave, the amplitude drops obviously, so it belongs to the second wave, which only affects the local shape of the cross section.
Table 4.7 Waveform Decomposition Parameters under Pulse 12 Fault
Note: A- amplitude; L- wavelength; β wave propagation direction (clockwise in X direction is positive).
From the wave decomposition parameters, it is also found that the ore body mainly has two directions, ore belt and ore body. One direction is SE48, and its amplitude is twice that of other directions, which plays a decisive role in the formation of ore-bearing space. The axial direction of the second propagation direction is SW63, which also plays an important role. This also explains the theoretical basis of the lateral distribution law of ore bodies analyzed in chapter 2. The propagation direction, wavelength and amplitude of primary and secondary waves determine the spatial distribution law of ore bodies, ore belts or ore bodies. The theoretical analysis is in good agreement with the actual exploration results.
The data and waveform functions in Table 4.7 are used to synthesize the known cross-sectional shape (Figure 4.52). The simulated section shape of the known section is in good agreement with the actual situation, and these parameters can be used for prediction. According to the analysis in Figure 4.53, gold ore bodies are mainly distributed in the upper right of the west uplift, the lower left of the east uplift and the lower part of the middle uplift.
(2) Expansion (ore storage) space simulation and orebody prediction and evaluation.
According to the research results of metallogenic geological conditions, the deep and extended parts of 12 vein are located, predicted and evaluated by using engineering control data to simulate fault morphology and activity.
Fig. 4.52 Q 12 simulated longitudinal projection of fracture morphology in pulse control area.
Firstly, the fracture surface morphology in the range of 0 ~ 2 500 m (relative coordinate position, the actual position depends on the distribution of exploration lines) and 0 ~ 65 438+0 600 m elevation is simulated, and the spatial distribution position of ore bodies is analyzed in detail. Figures 4.54 to 4.6 1 are vertical synthetic projections of the expansion space formed by normal fault slip, left shear, left slip, left thrust, right shear, right thrust, right slip and thrust simulating Q 12 pulse, as well as the isolines of linear metal quantity of ore bodies in known areas.
Through comparative analysis, the following forecast indicators are obtained:
The spatial distribution of 1) gold ore body is highly consistent with the expansion space formed by sinistral shear, sinistral thrust and normal fault slip. The tectonic activity is consistent with the field observation results.
2) The expansion space formed by the left thrust is located on the SE side, and it is a long lens in the southeast direction, forming an expansion space range with a length of 800m in the southeast and a width of about 600m in the southwest. The expansion space is distributed in beads along the southeast, and the distance between expansion and extrusion (unfavorable mineralization) is about 600m along the transverse direction.
Fig. 4.53 Q 12 vein fracture morphology simulation and vertical projection of linear metal quantity
Fig. 4.54 Q 12 vertical projection of the expansion space formed by normal fault sliding of vein ore-bearing fault and the distribution of known belt metal.
Fig. 4.55 Q 12 vertical projection of the expansion space formed by left-lateral shear of vein-like ore-bearing faults and the distribution of known belt metal.
Fig. 4.56 Q 12 vertical projection of the expansion space formed by the left thrust of the vein-like ore-bearing fault and the known distribution of belt metal.
According to the obtained prediction index, the blind mine prediction map with Q 12 pulse -2500 ~ 5000m (converted relative coordinate system) and elevation of 0 ~ 1600m was compiled (Figure 4.62). From the previous prediction, it can be seen that the main body of the expansion space formed by the left-handed thrust of the profile is in the southeast wing, with a lateral dip angle of about 50, which is controlled by the first-order wave, which is the dominant controlling factor for the emplacement of Q 12 vein ore bodies and controls the distribution of ore belts. There is only one ore belt within the control range, and there is no similar ore belt that controls known ore bodies at present. According to our theoretical analysis, the ore belt similar to this ore belt may develop in the southwest and northeast of this ore belt.
Fig. 4.57 Q 12 vertical projection of the expansion space formed by the left slip of the vein-like ore-bearing fault and the known distribution of belt metal.
Fig. 4.58 Q 12 vertical projection of the expansion space formed by right-lateral shear of vein ore-bearing fault and the distribution of known belt metal.
Fig. 4.59 Q 12 vertical projection of the expansion space formed by the right-lateral thrust of the vein-like ore-bearing fault and the known distribution of belt metal.
Fig. 4.60 Q 12 vertical projection of the expansion space formed by the right slip of the vein-like ore-bearing fault and the known distribution of belt metal.
Based on this, 9 target areas (points) are predicted, including 7 at the first level and 2 at the second level (Figure 4.62). Among them, the first-class target area is the most important, and its ore-hosting spatial range is very similar to the current Q 12 pulse control area, and the predicted resources are large. Specific coordinates are as follows:
I- 1: abscissa 500 ~ 1 100, elevation 0 ~ 600 m;
Fig. 4.6 1 Q 12 vertical projection of the expansion space formed by the thrust of vein-like ore-bearing faults and the distribution of linear metal in known areas.
I-2: abscissa 1800 ~ 2400, elevation 0 ~ 600 m;
I-3: abscissa -300 ~ 300, elevation 600 ~1200m;
I-4: abscissa-1400 ~1100, with an altitude of 500 ~ 800 meters;
I-5: abscissa -2300 ~ 1900, elevation1000 ~1400m;
I-6: abscissa 3000 ~ 3400, elevation 200 ~ 600 m;
I-7: abscissa 2300 ~ 2900, elevation 900 ~ 1400 m.
Like Q8 pulse, the predicted area delineated this time is the approximate range of the whole mineralization. As for a single ore body in this range, it is also affected by secondary waveform factors. That is to say, there is also the law of secondary enrichment of mineralization in the prediction area.