WO2022036939A1 - Ore prospecting method based on placer gold pointer mineralogy - Google Patents

Abstract

Disclosed is an ore prospecting method based on placer gold pointer mineralogy, which relates to the technical field of mineral resource exploration. By means of the method, the problem of it being impossible to quickly identify, by means of an existing ore prospecting method, a mineralization center of a gold deposit in a denudation region, and the problems of the low ore prospecting success rate and high costs are solved. Based on index parameters, such as the placer gold quantity, morphology, composition and inclusion assemblage, at different locations within an area to be explored, a graph of the placer gold quantity, the morphology, the composition and the inclusion assemblage as a function of a distance from the ore deposit is plotted, and a mineralization center is quickly and accurately delineated based on the plotted graph, thereby improving the ore prospecting efficiency and the ore prospecting success rate, and greatly reducing the exploration cost. The method is of great significance for efficient and low-cost gold deposit searching in areas with strong denudation and thick coverage in an orogenic belt.

Description

A prospecting method based on placer gold pointer mineralogy

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of 2 Chinese patent applications filed on August 18, 2020. The 2 Chinese patents are:

Patent 1: titled "A prospecting method based on placer gold pointer mineralogy", application number 202010829213.0; Patent 2: titled "A method for gold exploration in strongly eroded areas", application number 202010829193.7.

The entire contents of the above 2 patent applications are incorporated herein by reference.

technical field

The invention relates to the technical field of mineral resource exploration, in particular to a prospecting method based on placer gold pointer mineralogy.

Background technique

Epigenetic low-temperature gold deposits are usually produced in volcanic rocks or volcanic structures above gold-rich porphyry copper deposits, and the two together constitute a porphyry-epithermal low-temperature metallogenic system, which provides great opportunities for global industrial development. Some of the copper, gold, molybdenum and other metal resources are of great economic value and are one of the types of deposits with the longest exploration history and the most mature exploration technology. Therefore, it has been widely concerned by industry and academia. With the development of the national economy, the social demand for copper and gold resources is increasing substantially, while the outcrops and the easy prospecting in the shallow surface are becoming less and less, which makes the contradiction between the supply and demand of copper and gold resources increasingly prominent, and requires mineral exploration to The deep and thick coverage area is advanced to provide a new supply area of copper and gold resources. Although traditional geochemical exploration methods are still an important means to achieve breakthroughs in deep ore prospecting, because the surface geochemical anomalies in deep or thick coverage areas are often weak, traditional geochemical exploration methods are obviously difficult to apply. What followed was a sharp increase in the difficulty of prospecting, a sharp increase in exploration costs, and a dramatic drop in the discovery rate of exploration. The process of mineral exploration urgently required the emergence of efficient and low-cost prospecting methods. Research shows that epithermal deposits are not only an important source of precious metal resources, but also have important indications for deep porphyry copper deposits. Therefore, the effective identification of the porphyry-epithermal system mineralization center has always been an important part of porphyry copper metallogenic system research and ore prospecting exploration.

At present, relatively complete alteration zoning and mineral chemical markers/indicators have been established internationally for the identification of the existing porphyry-epithermal system mineralization centers. However, in the orogenic uplift environment with strong denudation, the rock outcrops are severely weathered, and a large number of slope deposits and alluvial deposits cover the surface. It increases the difficulty of using altered zoning or altered mineral geochemistry to trace the mineralization center. It is difficult to effectively identify the mineralization center of the porphyry-epithermal hydrothermal metallogenic system in the area where the structural uplift suffered strong erosion by using the existing alteration zoning and mineral chemical markers/indicators.

Therefore, how to effectively and quickly identify the mineralization center of the gold deposit metallogenic system in the strong denudation area has become a difficult problem faced by the current gold deposit exploration.

SUMMARY OF THE INVENTION

In view of the above analysis, the present invention aims to provide a prospecting method based on placer gold pointer mineralogy, to solve the problem that the existing prospecting methods cannot quickly identify the mineralization center of the gold deposit in the denudation zone, and the prospecting success rate is low and the cost is low. high question.

The object of the present invention is mainly achieved through the following technical solutions:

A prospecting method based on placer gold pointer mineralogy, comprising the following steps:

Based on the topographic features of the to-be-explored area, extract the water system in the to-be-explored area and delineate and divide the catchment basin, and obtain the distribution map of the water system and the catchment basin in the to-be-explored area;

In the water system distribution of the area to be explored and the limited range of the catchment basin, the natural heavy sand measurement of the water system is carried out to obtain the placer gold in a single set of samples;

According to the amount of placer gold in a single set of samples, determine the catchment basins with abnormal quantity of placer gold, and draw the distribution map of abnormal grades of placer gold in the catchment basin on the basis of the distribution map of water system and catchment basin in the area to be explored;

On the basis of the distribution map of placer gold anomaly grades in the catchment basin, using the quantity characteristics of placer gold to draw the sequence map of placer gold quantity distribution and delineate the rock gold mineralization area.

Further, using the mineral morphological characteristics of placer gold to draw the distribution map of placer gold morphological groups and delineate the rock gold mineralization area.

Further, drawing the distribution map of the morphological group characteristics of placer gold includes the following steps: dividing the morphological group types of placer gold according to the morphological characteristics of placer gold, and calculating the proportion of each type of morphological group of placer gold in a single group of samples, which is based on the distribution sequence diagram of placer gold quantity. Above, the morphological group type characteristics of placer gold were projected, and the distribution map of the morphological group type characteristics of placer gold was obtained.

Further, the principle of using the quantitative characteristics of placer gold to draw the placer gold quantity distribution sequence and delineate the rock gold mineralization area is as follows: the closer to the rock gold mineralization center, the higher the placer gold quantity level; the lower the level;

The types of placer gold morphological groups include primitive type, reformed type and remodeling type. The principle of using the characteristics of placer gold morphological groups to draw the distribution map of placer gold morphological groups and delineate the rock gold mineralization area is: the closer to the rock gold mineralization center, the more The greater the proportion of the original and transformed forms of placer gold.

Further, extracting the water system in the area to be explored and delineating and dividing the catchment basin includes the following steps: using software to automatically extract the water system data in the area to be explored and automatically delineating and dividing the catchment basin; Supplementary extraction and correction of water systems and catchment basins.

Further, carry out the measurement of natural heavy sand in the water system, and obtain the placer gold in a single group of samples, including the following steps:

Arrange sampling points on the distribution map of the water system and catchment basin in the area to be explored, and draw the sampling point layout map;

Collect samples to be processed at the set sampling points under GPS track monitoring;

The collected samples to be processed are processed to obtain placer gold in multiple single groups of samples.

Further, processing the collected samples to be processed to obtain the placer gold in a plurality of single-group samples includes the following steps:

The multiple groups of samples to be treated collected from the field were naturally air-dried, combed repeatedly with a wooden comb and mixed evenly, and the multiple groups of samples to be treated were weighed with the same weight to obtain multiple single-group samples;

Multiple single groups of samples are screened with cylindrical sieves to separate the gravel and sediment, and the sand and mud parts under the sieve of a single group of samples are subjected to rough elutriation, magnetic separation, electromagnetic separation, fine elutriation, and heavy liquid separation. And binocular identification and selection, to get multiple single-group samples of placer gold.

Further, determining a catchment basin with an abnormal quantity of placer gold includes the following steps: classifying the catchment basin according to the quantity abundance of placer gold in the catchment basin;

The formula for calculating the abundance of placer gold is:

R=N/(n×m),

Among them, R is the abundance of placer gold; N is the total number of placer gold produced in a single catchment basin; n is the total number of sample groups in a single catchment basin; m is the weight of a single group of samples.

Further, after delineating the rock gold mineralization zone, the following steps are also included:

On the basis of the distribution map of placer gold anomaly grades in the catchment basin, the mineralogical characteristics of placer gold are used to delineate the rock gold mineralization area and narrow the scope of the prospecting target area.

Further, using the mineralogical characteristics of placer gold to delineate the rock gold mineralization area and narrow the scope of the prospecting target area include the following steps:

Scanning electron microscope was used to observe the standard round target of placer gold epoxy resin, and the mineralogy characteristics of placer gold core were statistically analyzed. , draw the mineralogical characteristics distribution map of the placer gold core, delineate the rock gold mineralization area, and narrow the scope of the prospecting target area.

Further, after determining the catchment basin with abnormal amount of placer gold, the following steps are also included:

In a catchment basin with an abnormal amount of placer gold, the transportation distance of placer gold and the suspected rock-gold mineralization area are preliminarily estimated by using the roundness, sorting and composition of the gravel group associated with placer gold, and the suspected rock-gold mineralization area is preliminarily delineated; The principle is:

The higher the proportion of wear-resistant components in the gravel, the better the roundness and sorting, and the longer the transport distance of placer gold; the lower the proportion of wear-resistant components in the gravel, the better the roundness and sorting. The worse the property is, the closer the placer gold is transported.

Further, after the delineation of the rock-gold mineralization area, the following steps are further included: verifying the delineated rock-gold mineralization area by means of a geophysical prospecting method, and narrowing the scope of the prospecting target area.

Further, before using the geophysical method to verify the delineation results, elemental analysis was carried out on the placer gold epoxy resin target to obtain the geochemical characteristic parameters of the placer gold, and the geochemical characteristics of the placer gold were used to discriminate the mineralization type of the rock-gold mineralization zone;

The mineralization type of the rock-gold mineralized area is used as the basis for geophysical verification in the delineated rock-gold mineralized area.

Further, the mineralization types of the rock-gold mineralization zone include three types of epithermal gold deposits, porphyry copper-gold deposits, or epithermal gold-porphyry copper-gold composite gold deposits;

If the mineralization type of the rock-gold mineralization area is an epithermal gold deposit with low temperature, the geophysical prospecting or drilling method shall be adopted in the delineated rock-gold mineralization area to continue to explore the porphyry copper-gold deposit;

If the mineralization type of the rock-gold mineralization area is a porphyry copper-gold deposit, it is not necessary to continue to explore the epigenetic low-temperature hydrothermal gold deposit in the delineated rock-gold mineralization area;

If the mineralization type of the rock-gold mineralization area is an epigenetic low-temperature hydrothermal gold ore-porphyry-type copper-gold complex gold deposit, the epigenetic low-temperature thermal exploration should be continued in the delineated rock-gold mineralization area in combination with other geological data as the case may be. Liquid gold deposits and porphyry copper-gold deposits.

Compared with the prior art, the present invention has at least one of the following beneficial effects:

a) The prospecting method based on placer gold pointer mineralogy provided by the present invention, uses placer gold mineralogy to identify the mineralization center of porphyry-epi-low temperature hydrothermal metallogenic system, specifically through the number distribution sequence of placer gold in the water system sediments of the exploration area , systematic research on placer gold mineral morphology, mineral geochemistry, etc., to find out the amount, size, morphology, type and quantity of mineral inclusions at different locations, and the distribution and variation of main and trace elements of placer gold alloy in the core, and compile the number, size, shape, and distribution of placer gold. The graph of the relationship between morphology, composition, inclusion combination and deposit distance, establishes a method for identifying gold deposit mineralization centers using placer gold mineralogy, which can quickly and accurately delineate mineralization centers, greatly reduce exploration costs, and significantly improve exploration efficiency.

b) The ore prospecting method based on placer gold pointer mineralogy provided by the present invention comprehensively utilizes the quantity of placer gold, placer gold mineralogy, and placer gold geochemical characteristic indexes in the water system sediments to delineate the rock gold mineralization area, and combines the geophysical prospecting method to explore the hidden areas in the thick coverage area Porphyry-epihydrothermal deposits can gradually and accurately narrow the prospecting target area, provide a basis for better layout of drilling projects, reduce the number of exploration drilling, greatly reduce exploration costs, and significantly improve the porphyry- The exploration efficiency of epithermal ore bodies or deposits.

c) The prospecting method based on placer gold pointer mineralogy provided by the present invention, before using the geophysical prospecting method to verify the results of the delineated rock gold mineralized area, by judging the mineralization type of the rock gold mineralized area, the rock gold mineralization The mineralization type of the chemical area is used as the basis for geophysical exploration and verification in the delineated rock gold mineralization area, which is helpful for the next step to carry out the geophysical exploration and drilling detailed investigation project, avoid blindly carrying out geophysical exploration and drilling, and greatly reduce the exploration cost. .

In the present invention, the above technical solutions can also be combined with each other to achieve more preferred combination solutions. Additional features and advantages of the invention will be set forth in the description which follows, and some of the advantages may become apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by means of particularly pointed out in the description and drawings.

Description of drawings

The drawings are for the purpose of illustrating specific embodiments only and are not to be considered limiting of the invention, and like reference numerals refer to like parts throughout the drawings.

Fig. 1 is the flow chart of a kind of prospecting method based on placer gold pointer mineralogy of the present invention;

Fig. 2 is the gold dust sampling and processing flow chart in the embodiment of the present invention;

Fig. 3 is a schematic diagram of the number distribution sequence of placer gold in the embodiment of the present invention;

Fig. 4 is a schematic diagram of the distribution of gold placer morphology groups in the embodiment of the present invention;

Fig. 5 is the distribution map of the water system and catchment basin in the Duolong ore concentration area in the embodiment of the present invention;

FIG. 6 is a sequence distribution diagram of anomalous grade of placer gold and the distribution of placer gold quantity in the catchment basin of the Duolong ore concentration area in the embodiment of the present invention.

detailed description

The preferred embodiments of the present invention are specifically described below with reference to the accompanying drawings, wherein the accompanying drawings constitute a part of the present application, and together with the embodiments of the present invention, are used to explain the principles of the present invention, but are not used to limit the scope of the present invention.

Example 1

A specific embodiment of the present invention discloses a prospecting method based on placer gold pointer mineralogy, which is suitable for gold prospecting in denuded areas, as shown in Figure 1, including the following steps:

Step 1: Based on the geological metallogenic law and combined with the existing regional geological data, determine the favorable mineralization area to be explored.

Based on the geological metallogenic law and combined with the existing regional geological data, the exploration areas that have undergone strong denudation are selected. For example, porphyry-epigenetic low-temperature hydrothermal ore is selected as the to-be-explored area. The exploration area is located in a known large-scale metallogenic belt or ore concentration area; there are known porphyry or epithermal deposits in the surrounding area; the area to be explored is subject to strong weathering and denudation, and the water system gullies are developed; the placer gold is widely distributed in the area to be explored .

Step 2: Based on the topographic features of the to-be-explored area, extract the water systems developed in the to-be-explored area and delineate and divide the catchment basins to obtain the distribution map of the water systems and catchment basins in the to-be-explored area.

The scope of the catchment basin refers to the surface runoff collection area formed by natural precipitation under the action of the watershed. The formation of natural water system basins is strictly restricted by the scope of the catchment basin. Generally, the number of catchment basins is multiple.

Use the software to automatically extract the water system data of the area to be explored and automatically delineate and divide the catchment basin. Specifically, in the to-be-explored area where porphyry-epigenetic low-temperature hydrothermal deposits are favorable for mineralization, use the 91 satellite map assistant (or use other spatial databases) to extract the elevation data (DEM data) of the selected area to be explored, and then use Global Mapper software analyzes the elevation data of the to-be-explored area, and extracts the topographic data of the to-be-explored area; then uses the Global Mapper software to further extract the water system data of the to-be-explored area according to the extracted topographic data, and automatically delineates and divides the catchment basins to obtain the to-be-explored area. Distribution map of the water system and catchment basin in the area, the scale bar is 1:50,000.

In order to improve the accuracy of water system extraction and catchment basin delineation, on the basis of the results of automatic extraction of water system and catchment basin delineation by the software, supplementary extraction, correction and revision of water systems and catchment basins in the exploration area are carried out in combination with the artificial visual topography method. , the specific operations are: on the basis of the automatic extraction of water systems and the delineation of catchment basins by the Global Mapper software, the topographic and geomorphological features are manually viewed, the gully trajectories are manually drawn, the watershed ridge lines are drawn, and the results obtained by the software are manually checked and corrected. , to achieve accurate extraction of water systems in the exploration area and accurate establishment of catchment basins, so that the distribution map of water systems and catchment basins in the exploration area is more accurate.

Step 3: Carry out the natural heavy sand measurement of the water system within the range of the water system distribution in the to-be-explored area and the catchment basin to obtain the placer gold in a single group of samples; determine the placer gold according to the amount of placer gold in a single group of samples in each catchment basin The number of anomalous catchment basins is drawn, and the distribution map of placer gold anomaly grades in the catchment basin is drawn on the basis of the water system and the distribution map of the catchment basin in the area to be explored.

Step 31: According to the distribution of the extracted water system and the division of the catchment basin in the selected area to be explored, carry out the natural heavy sand measurement of 1:50,000 water system, and obtain the placer gold in multiple single-group samples. Among them, the measurement steps of natural heavy sand of water system are:

Step 311 : Layout sampling points on the distribution map of the water system and catchment basin in the area to be explored, and draw a sampling point layout map.

On the distribution map of the water system and catchment basin in the to-be-explored area, the sampling points are arranged along the trajectory of the water system and gullies in the to-be-explored area. The spatial layout of the sampling points takes into account the metallogenic factors such as favorable strata, structures, magmatic rocks, and mineralization points. The layout density of points is thinned from the favorable metallogenic area to the periphery. The base map of 1:50,000 is used, and the density is thinned from 200m to 2000m. The point spacing is not strictly set, and the areas with high metallogenic potential can be properly densified and laid. Convert the sampling point layout map to hand map and import it into the mobile phone terminal for field sampling.

Step 312 : collect samples to be processed at the set sampling points under GPS track monitoring.

The sampling process is shown in Figure 2. Taking the center of the design sampling point as the center of the circle, select the most favorable deposition location of alluvial gold in a circle with a radius of 5m (such as the turning convex of the water system, the upstream of the central bank, and the intersection of the water system), and plan it first. The surface layer is about 5cm thick sedimentary layer, and then dig a shallow pit with a radius of 0.2-0.3m and a depth of 0.3-0.5m to collect the samples to be processed, and use a cylindrical sieve with a sieve aperture of 8mm and a diameter of 30cm to control the particle size of the sample to 8mm. Below, the sieved sample particles are double-packed in plastic bags and cloth bags, and then marked with the sample number; the whole sampling process is monitored by GPS track, and the location of the sampling point, the number of the sampling point and the sample bag, and the sampling tool are overall photographed and recorded by a digital camera; A set of heavy sand samples is collected from each sampling point. The quality specification of the sampling points is that the weight of each group of natural heavy sand samples is controlled at 12-15Kg. The weight of each group of natural heavy sand samples is controlled according to the water content of the heavy sand samples, at least satisfying The weight of each group of samples after air-drying is greater than 10Kg; according to the total number of sampling points, a corresponding number of duplicate samples are collected, and the sampling is repeated once in the vicinity of the same sampling point to achieve at least 10% coverage of duplicate samples to evaluate the quality of placer gold sampling, for example For each 100 sets of samples, at least 10 sets of duplicate samples should be collected; after the collection of each sampling point during the sampling process, the sampling tools should be strictly cleaned to prevent cross-contamination.

Step 313: Process the collected samples to be processed to obtain placer gold in a single set of samples.

Since there are impurities such as gravel and silt in the heavy sand samples in addition to the target placer gold, the placer gold is sorted and purified for each group of samples to obtain the placer gold in a single group of samples. Specifically, the multiple groups of samples collected from the field were naturally air-dried, and the single group of samples was repeatedly combed with a wooden comb and mixed evenly. After each group of samples was evenly mixed, the multiple groups of samples were respectively weighed to the same weight to obtain multiple single-group samples. For example, 10Kg is strictly weighed, and the excess part is kept as a sub-sample for checking the analysis results. The multiple single groups of samples weighed in equal weight are respectively screened with a cylindrical sieve to separate the gravel and sediment. In this step, the sieve aperture of the cylindrical sieve is 2 mm, and the diameter of the cylindrical sieve is 30 cm. The particle size of the particles on the screen is 2-8 mm, and the particle size of the particles under the screen is less than 2 mm. The sand and mud parts under the sieve of a single group of samples were subjected to rough panning, magnetic separation, electromagnetic separation, fine panning, heavy liquid separation, and binocular identification and selection, respectively, to obtain the placer gold in multiple single-group samples. The whole process can only be air-dried naturally to avoid high temperature damage to the original characteristics of minerals and to ensure the accuracy and reliability of subsequent test results.

Step 32: Count the sum of the amount of placer gold in each catchment basin, determine the catchment basin with abnormal placer gold quantity according to the abundance of placer gold, and draw the distribution of anomalous level of placer gold in the catchment basin on the water system distribution and catchment basin map of the area to be explored picture.

The obtained heavy concentrate (that is, the heavy part recovered after heavy-liquid separation, containing heavy minerals such as placer gold, cinnabar, galena, limonite) is respectively identified under a stereomicroscope and sorted, purified and counted, or, using The Mineral Dissociation Analyzer (MLA) performed the identification count of placer gold. Then, the sum of the amount of placer gold in each catchment basin is counted, and the catchment basins are classified according to the abundance of placer gold in the catchment basin, as shown in Table 1, and then the catchment basins with abnormal amount of placer gold are determined. Among them, the abundance of placer gold R refers to the amount of gold produced per kilogram of heavy sand sample, and the calculation formula is:

R=N/(n×m),

Among them, R is the abundance of placer gold; N is the total number of placer gold in a single catchment basin; n is the total number of samples in a single catchment basin; m is the weight of a single set of samples, which is 10Kg.

Table 1 Classification of abnormal levels of placer gold in catchment basins

exception level	Placer gold number abundance R (grain/Kg)
Level 4 abnormality	R≥2Rb

Level 3 abnormality	R b ≤ R < 2R b
secondary abnormality	(1/3) R b ≤ R < R b
Level 1 abnormality	0＜R＜(1/3)R b

The total amount of placer gold produced by all sampling points in the exploration area is counted to obtain the background value R ^b of placer gold abundance in the exploration area. Among them, the background value of the abundance of placer gold, R ^b , refers to the amount of gold produced per kilogram of heavy sand samples in all placer gold sampling points in the to-be-explored area. The calculation formula is:

R ^b =N ^t /(n ^t ×m),

Among them, R ^b is the background value of the abundance of placer gold; N ^{t is} the total amount of placer gold produced in the area to be explored;

Compare the abundance of placer gold in each catchment basin with the background value of placer gold abundance R ^b in the entire area to be explored. When the abundance of placer gold in the catchment basin is greater than or equal to the background value of placer gold abundance in the entire area to be explored, R When it is twice as large as ^b , it is defined as the fourth-level anomalous catchment basin of placer gold; when the number abundance of placer gold in the catchment basin is greater than or equal to 1 times of ^Rb but less than 2 times of ^Rb , it is defined as the third-level anomalous catchment of placer gold Basin; when the quantity abundance R of placer gold in the catchment basin is greater than or equal to 1/3 of R ^b but less than 1 times of R ^b , it is defined as the secondary abnormal catchment basin of placer gold; when the quantity abundance R of placer gold in the catchment basin is greater than When 0 is less than 1/3 of R ^b , it is defined as the first-level anomalous catchment basin of placer gold, see Table 1 for details. Exemplarily, the background value R ^b of the abundance of placer gold in a certain area to be explored is 0.96. According to the R value of the abundance of placer gold in each catchment basin, the abnormal level of the catchment basin is determined, as shown in Table 2.

Table 2 An example of the classification of abnormal levels of placer gold in catchment basins

exception level	Abundance of placer gold number R (grain/Kg), R b = 0.96
Level 4 abnormality	R≥1.92
Level 3 abnormality	0.96≤R＜1.92
secondary abnormality	0.32≤R＜0.96
Level 1 abnormality	0＜R＜0.32

According to the abnormal level of placer gold quantity in the catchment basin divided in Table 1, use the drawing software to draw the distribution map of the abnormal level of placer gold in the catchment basin on the water system distribution and catchment basin map in the area to be explored.

Step 4: In a catchment basin with an abnormal amount of placer gold, use the roundness, sorting and composition of gravel groups associated with placer gold to preliminarily infer the transport distance of placer gold and the suspected placer gold source area, and preliminarily delineate the suspected rock gold mineralization area.

In the placer gold anomaly catchment basin, the gravel particles with a particle size of ≥ 2 mm in each group of samples were spread on a stainless steel plate with a width of 30 cm and a length of 50 cm, and were repeatedly combed and mixed evenly, and the rounding of the gravel groups in the statistical samples was observed. The degree, sorting and composition were determined, and the grid method (10cm×10cm) was used to randomly select several particles with a particle size of 4-8mm from the gravel of different components in a single group of samples to grind rock slices respectively, and conduct petrographic observation. Obtain the petrological composition of the gravel. Among them, 1-3 pieces of each grid are selected, and a total of 3-6 pieces of gravel of each composition are selected.

Since the longer the transportation distance, the higher the proportion of the anti-erosion components in the gravel, such as quartz and chert, the better the roundness and sorting performance. From this, the transportation distance of the placer gold associated with the gravel can be indirectly inferred. . The higher the proportion of wear-resistant components in the gravel, the better the roundness and sorting, and the longer the transport distance of placer gold. On the contrary, the lower the proportion of wear-resistant components in the gravel, the better the roundness And the worse the sorting, the closer the placer gold is transported.

Because the gravel contains natural gold or minerals that are closely symbiotic with natural gold, such as pyrite, arsenopyrite, chalcopyrite, galena, sphalerite, etc., it is a direct sign indicating the source area of the placer gold parent rock. Exemplarily, three types of gravel, sandstone, granodiorite porphyry, and siliceous rock are produced in the collected samples. The three types of gravel are sampled by grid method, and rock slices are respectively ground for petrographic observation. Natural gold or minerals closely symbiotic with natural gold are found in granodiorite porphyry, such as pyrite, arsenopyrite, chalcopyrite, galena, sphalerite, etc., while there is no natural gold in sandstone and siliceous rock. Gold or minerals closely symbiotic with native gold, it can be inferred that the parent rock of placer gold is mainly granodiorite porphyry, and further combined with the roundness and sorting of granodiorite porphyry gravel, it can be inferred that placer gold is The transportation distance of the gravel, the worse the roundness and sorting of the gravel, the closer the transportation distance of the placer gold, and the closer it is to the source area of the parent rock, thus providing a basis for the location of the source area of the parent rock of the placer gold.

Step 5: Draw the placer gold quantity distribution sequence map and delineate the rock gold mineralization area based on the placer gold quantity distribution sequence map based on the placer gold quantity distribution sequence map in the catchment basin on the placer gold anomaly grade distribution map; or, on the basis of the placer gold quantity distribution sequence map Using the mineral morphological characteristics of placer gold to draw the distribution map of placer gold morphological group characteristics and delineate the rock gold mineralization area.

Step 5.1: On the basis of the distribution map of anomalous levels of placer gold in the catchment basin, draw a sequence diagram of the distribution of placer gold quantity.

In a catchment basin with an abnormal amount of placer gold, map the amount of placer gold produced in each sampling point in the catchment basin according to the actual sampling coordinates. The specific projection steps are as follows: take the distribution map of the abnormal level of placer gold in the catchment basin as the base map of the placer gold quantity projection, firstly classify the placer gold quantity according to the quantity of placer gold output at a single sampling point, and then draw a solid center with the sampling point as the center Circle, the radius of the solid circle is positively correlated with the grade of placer gold quantity, that is, the higher the grade of placer gold quantity, the larger the radius of the solid circle, and the larger the area of the solid circle, thus the quantity distribution sequence of placer gold in the catchment basin can be obtained. As shown in Figure 3, if the background color is dark, the solid circle is a white solid circle.

Among them, the grading of the amount of placer gold is determined according to the actual maximum output quantity of placer gold in a single sampling point. Exemplarily, the maximum output quantity of placer gold in a single sampling point is 400 grains, and the quantity grade of placer gold can be classified from low to high as: Six grades: 0, 1; 2-5; 6-20; 21-50; 51-400, corresponding to grade 0, grade I, grade II, grade III, grade IV, and grade V, respectively. The solid circle radii for grades I to V are shown in Table 3. In order to display the samples with no placer gold particles in the sequence diagram of the number distribution of placer gold, take the center of the sampling point with grade 0 as the center of the circle, and draw the center point of the white solid circle as a black point, which is called the black center circle. As shown in Figure 3 or Figure 6, the radius of the black circle is less than or equal to the radius of the I-level solid circle.

Table 3 Quantity and grade classification of placer gold

Gold duster quantity grade	The maximum output of gold placer from a single sampling point is 400 grains	Solid circle radius/mm
Class V	51-400	3
Level IV	21-50	2
Class III	6-20	1.5
Class II	2-5	1
Class I	1	0.75
Level 0	0	/

The abundance of placer gold particles and the change of placer gold quantity can reflect the spatial relationship of gold deposits in different denudation areas and the distance from the mineralization center. From the placer gold quantity distribution sequence on the placer gold quantity distribution sequence map in the catchment basin, the rock-gold mineralization area can be preliminarily inferred, that is, the closer to the rock-gold mineralization center, the higher the placer gold quantity grade; The farther away, the lower the placer gold quantity grade; overall, from the rock gold mineralization center outward, the placer gold quantity grade shows a decreasing trend.

Step 5.2: On the basis of the sequence diagram of the number distribution of the placer gold, draw the distribution map of the characteristics of the placer gold morphological group.

Step 5.2.1: Observing the morphological characteristics of the placer gold produced by each group of samples, and counting the size, appearance and morphological information of the placer gold.

During the migration process of placer gold, its outer surface is affected by external conditions, and the migration distance affects the morphology of placer gold particles. All the placer gold produced at each sampling point were observed and counted under the stereo microscope in size, appearance and morphology, including the overall shape, outline, roundness, and edge curling degree of the gold placer; A representative 5-20 gold placer is used to observe the microscopic morphology of the selected placer gold by using scanning electron microscope (SEM), backscattering and other fine microscopic observation methods. Among them, the selection of gold placer quantity is determined according to the quantity and size of gold produced in each group of samples. The greater the quantity of gold produced, the more gold placer is selected. If the quantity of gold produced in the sample is less than 5, all should be selected; The higher the number, to avoid inaccurate test results due to too small particles. Scanning Electron Microscope (SEM) observation content of placer gold includes: surface smoothness of placer gold, original crystal plane and gangue impression, edge curling and other topographic information, and measurement of three-dimensional parameters of length, width and height of placer gold to calculate the flatness of placer gold Index CFI (Cailleux's flattening index), the calculation formula of flatness index CFI is: CFI=(L+W)/2T, where L is the long axis length of placer gold, um; W is the short axis length of placer gold, um; T is the thickness of placer gold, um. From the mineralization center to the periphery, along the flow direction of the water system, with the increase of the transportation distance, the flatness index of placer gold has a gradually increasing trend.

Step 5.2.2: Divide the morphological group types of placer gold according to the morphological characteristics of placer gold, and count the proportion of each type of morphological group of placer gold in a single group of samples. Make a map, draw the distribution map of the type characteristics of placer gold morphological groups and delineate the rock gold mineralization area.

The types of placer gold morphological groups include primitive type, transformation type and remodeling type, and the specific division is based on:

(1) Primitive type: angular linear or rod-shaped or thin leaf-shaped, smooth surface, and retains the original crystal plane and gangue impression, and may also be wrapped with some gangue minerals such as quartz, and the flatness is mostly 1 ~3.5.

(2) Transformation type: the edge of the gold placer becomes curled and passivated, the particles may be wrinkled and bent, a small amount of pockmarks appear on the surface, and the surface stripes develop, the surface is felt-like, the original crystal plane basically disappears, and the contour of the crystal impression becomes Round and blunt, with a flatness of 3 to 8.

(3) Remodeling type: All the above-mentioned original surface structures have disappeared, the edges of the particles are severely curled, the contours are mostly elliptical or nearly circular, and the surface cracks are developed. Rod-shaped, with a large number of pockmarks distributed on the surface of the particles, and the flatness is greater than 5.

From the mineralization center to the periphery, along the flow direction of the water system, original placer gold, reformed placer gold, and remodeled placer gold appeared in sequence. That is to say, with the increase of the carrying distance of the placer gold, the placer gold transitions from the original type to the transformed type, and then from the transformed type to the remodeled type. When the transport exceeds a certain distance, the surface contour of the placer gold is elliptical or nearly circular.

Based on the proportion of placer gold morphological groups in a single group of samples, the proportion of primitive placer gold is used as an indicator index, and on the basis of the sequence map of placer gold quantity distribution in the catchment basin, the characteristics of a single group of placer gold morphological groups are projected to draw placer gold. Morphological group characteristic distribution map.

The specific mapping steps for drawing the characteristic distribution map of placer gold morphological groups are as follows: first, the morphological group grades are divided according to the proportion of primitive placer gold in a single group of samples, and the proportion of primitive placer gold is divided into three grades from high to low: Grade III ≥ 90%; Level 2 30%-90%; Level 1≤30%, then draw a hollow circle with the center of each sampling point as the center. The higher the level, the larger the radius of the hollow circle and the larger the area of the hollow circle, as shown in Table 4 shown.

Table 4 Classification of morphological groups of placer gold

Gold Dust Form Group Level	Proportion of original placer gold in a single sampling group (%)	Radius of circle/mm
Class III	[90, 100]	3
Class II	(30, 90)	2
Class I	[0, 30]	1.5

From this, the distribution characteristic map of placer gold morphological groups in the catchment basin as shown in Figure 4 is obtained. From the distribution of placer gold morphological groups on the distribution characteristic map of the placer gold morphological group in the catchment basin, the rock-gold mineralization area can also be preliminarily inferred, that is, the closer to the rock-gold mineralization center, the higher the placer-gold morphological group grade; The farther from the center, the lower the gold dust formation cluster level.

The rock-gold mineralization area can be delineated through the sequence characteristics of placer gold quantity distribution shown in Figure 3, the distribution characteristics of placer gold morphological groups shown in Figure 4, and the analysis results of gravel groups. The rock-gold mineralization area has the following characteristics: the closer it is to the rock-gold mineralization center, the higher the quantity grade of placer gold, the larger the particle size, the higher the grade of placer gold form group, and the greater the proportion of original and transformed form of placer gold. If the projection results of Figure 3 and Figure 4 show that individual pointer indicators do not meet the above conditions, and there is an abnormal data area, then use the retained sub-sample of the abnormal data area to perform statistical observation, re-sampling verification, or combine other geochemical Means and geophysical means to further determine the rock-gold mineralization area.

Step 6: Use scanning electron microscope (SEM) to observe the placer gold epoxy resin round target, statistically analyze the mineralogy characteristics of placer gold core, the distribution map of placer gold abnormal grade, the sequence map of placer gold quantity distribution and/or the distribution of placer gold morphological groups in the catchment basin On the basis of the feature map, draw the mineralogical feature distribution map of the placer gold core, delineate the rock-gold mineralization area, and narrow the scope of the prospecting target area.

Since all or part of the mineralogy information of the source area mineralization and epigenesis can be preserved during the formation of placer gold, the mineral composition, occurrence and metasomatism in placer gold can reflect the mineralization and epigenesis of the source area to a certain extent. There are also differences in the morphological characteristics of placer gold in the porphyry-epihydrothermal metallogenic center and periphery. Through fine microscopic observation of representative placer gold particles such as scanning electron microscopy and backscattering, combined with energy spectrum analysis, the mineral composition, occurrence and metasomatism in placer gold were systematically identified. The outer surface of the placer gold is affected by external conditions during the handling process, and a thin layer of high-purity gold shell structure is often formed on the outer edge of the placer gold. Mineral inclusions such as pyrite, galena, chalcopyrite and other sulfide minerals are becoming less and less.

In this step, 5-10 gold placer particles are randomly selected from a single set of samples collected in the catchment basin with abnormal amount of placer gold to make a standard epoxy resin placer gold round target. Satisfying the current analysis technology can achieve better analysis results. The epoxy resin round target of placer gold was observed under scanning electron microscope (SEM), and the type and quantity of mineral inclusions in the core of placer gold and the structural parameters (such as thickness) of the gold shell of placer gold were statistically analyzed. , quantity and gold shell structure parameters of placer gold were put into the distribution map of placer gold anomaly grade/distribution characteristic map of placer gold morphological group in the catchment basin, and the distribution map of mineralogy characteristics of placer gold core was obtained. In the gold mineralized area, the scope of the prospecting target area shall be reduced.

The mineralogical characteristic distribution map of the placer gold core in the catchment basin is used to further delineate and narrow the rock-gold mineralization area. The number of inclusions is increasing; the farther away from the center of rock gold mineralization, the thicker the gold shell structure, and the number of inclusions of unstable minerals in placer gold is less and less. The exploration method of this embodiment is more accurate to delineate the rock gold mineralization zone by comprehensively considering the mineralogical characteristics of placer gold, the map of placer gold quantity distribution sequence, the map of placer gold morphology distribution, and the characteristics of gravel groups.

It should be noted that, in this embodiment, the distribution map of placer gold anomaly levels in the catchment basin, the sequence map of placer gold quantity distribution, the distribution map of placer gold morphological group characteristics, and the map of mineralogy characteristics of placer gold cores can be superimposed and drawn in sequence, or they can be drawn separately only in Draw on the distribution map of the water system and catchment basin in the area to be explored, and you can also select two or more maps to be superimposed and drawn.

Compared with the prior art, the prospecting method based on placer gold pointer mineralogy provided in this embodiment takes the porphyry-epi-low temperature hydrothermal metallogenic area in the strong denudation area where placer gold is widely distributed as the exploration object, and uses placer gold mineralogy to identify it. The gold mineralization center conducts systematic research on the morphology and mineral geochemical indicators of placer gold in the sediments of modern water systems in the mining area to be explored. The distribution map of mineral inclusions and major trace elements, revealing the mineralogical signs of placer gold at different migration distances, and successfully constructing an exploration model and method system for gold mineralization centers based on placer gold morphology and mineral chemistry. It is of great significance to provide new ideas for finding gold deposits at high efficiency and low cost in the covered area.

Example 2

Another specific embodiment of the present invention, on the basis of the prospecting method in Example 1, combined with the geophysical prospecting method to verify the delineation results of the rock gold mineralized area, which can not only improve the prospecting accuracy, but also greatly improve the traditional prospecting efficiency. . Specifically, the prospecting method of this embodiment includes steps 1 to 6 of Embodiment 1, and further includes the following steps:

Step 7: Use the geophysical method to verify the results of the delineated rock-gold mineralization area, and narrow the scope of the prospecting target area.

After using the prospecting method of Example 1 to determine the delineated rock-gold mineralized area and determine the mineralization type of the rock-gold mineralized area, the geophysical prospecting method is used to continue the exploration in the delineated rock-gold mineralized area. The magnetotelluric sounding method (AMT) is used to delineate the low-resistance mineralization alteration zone of the rock-gold ore body, further narrow the prospecting target area, further delineate the position of the mineralization body, and approach the mineralization center.

Specifically, in the rock-gold mineralized area delineated by the method of Example 1, a 1:10000 audio frequency magnetotelluric profile was performed. First, the length and arrangement direction of the profile were determined according to the delineated rock-gold mineralized area, and then a 1:10000 audio frequency was performed. 10000 audio frequency magnetotelluric profile measurement, comprehensive processing and inversion interpretation of the obtained geophysical data, obtaining deep electrical structural characteristics, combined with comprehensive analysis of existing geological data, delineating low-resistance mineralization alteration zones, and searching for deep hidden porphyry bodies , explore the relationship between deep structures and ore bodies, evaluate the resource potential within 2500 meters below the surface of the delineated rock-gold mineralization area, further narrow the prospecting target area and provide a basis for better arrangement of drilling projects, so as to achieve strong denudation and thick coverage area Rapid delineation of porphyry-epithermal ore bodies or deposits.

Since the mineral inclusions in placer gold are essentially microscopic mineral symbiotic assemblages, it is an effective indicator to distinguish the mineralization type of placer gold source area (rock gold mineralization area). If the copper ore ± kaolinite ± dickite ± alunite is observed in the placer gold, it can be preliminarily inferred that the placer gold source area is a high-sulfur epithermal deposit; if the placer gold contains ice feldspar ± calcite ± quartz, It can be preliminarily speculated that the placer gold source area is a low-sulfur epithermal deposit; and the placer gold contains bornite ± chalcopyrite ± pyrite, but no other such as chalcopyrite, dickite, alumite, ice Feldspar and other epithermal hydrothermal characteristic minerals can preliminarily infer that the placer gold source area is a porphyry copper-gold deposit.

Therefore, in order to improve the efficiency of geophysical exploration and reduce the cost of exploration, in the prospecting method of this embodiment, before step 7, the mineralization type of the rock-gold mineralization area that has been delineated is judged, and the mineralization type of the rock-gold mineralization area is used as whether it is in The basis for geophysical verification of the delineated rock-gold mineralized area. In this example, elemental analysis was performed on the placer gold epoxy resin target in step 6 of Example 1, and the geochemical characteristic parameters of placer gold were obtained. According to the type of deposits in the rock-gold mineralization area, the next stage of exploration work will be deployed in a targeted manner, so as to avoid blindly carrying out geophysical prospecting and drilling, and greatly reduce exploration costs. Specifically include the following steps:

For the placer gold epoxy resin target analyzed under scanning electron microscope (SEM), X-ray fluorescence spectroscopy (XRF) was used to further analyze the main elements of the placer gold core; or, electron probe (EPMA) or laser ablation inductively coupled plasma was used. Mass spectrometer (LA-ICPMS), after the calibration of the corresponding laboratory standard samples, analyzes the main and trace elements in the placer gold core, and obtains the types and contents of the main elements in the placer gold core. The main elements include Au, Ag, Cu, and Hg. Based on the main element content data, the fineness of the placer gold core is calculated. The fineness of the placer gold core represents the fineness of the natural gold in the placer gold source area. The fineness of natural gold is a powerful indicator to distinguish mineralization types. The color range of placer gold in porphyry copper-gold deposits varies from 650 to 1000, while the color range of epithermal gold deposits varies from 440 to 1000. The types and contents of alloying elements in the core of placer gold are also effective indicators to distinguish the types of mineralization. The placer gold produced from epithermal deposits has the characteristics of low Cu, rich Au, and large changes in Ag content; while the porphyry copper-gold deposits have high Cu, The content of Au and Ag varies greatly.

In the prospecting method of this embodiment, it can be determined that the placer gold source area is an epigenetic low-temperature hydrothermal gold deposit, a porphyry copper-gold deposit, or both contributed by considering the combination of mineral inclusions in the core of placer gold and the characteristics of main and trace elements. complex gold deposits. Because epithermal gold deposits are usually produced in volcanic rocks or volcanic structures above gold-rich porphyry copper deposits, the two together constitute a porphyry-epihydrothermal metallogenic system. If the placer gold composition identification indicates that the delineated rock-gold mineralization area has only epithermal hydrothermal source area, that is, a porphyry copper-gold deposit, there may also be porphyry copper-gold mineralization in the deep part, and it is necessary to take measures within this range. Continue to explore porphyry copper-gold deposits with geophysical prospecting or drilling methods; if placer gold composition identification indicates that the delineated rock-gold mineralization area has only porphyry mineralization source area, that is, porphyry-type copper-gold deposits, it indicates porphyry-epigenic low temperature The hydrothermal system is not fully developed and lacks the overlying epithermal hydrothermal part, so it is not necessary to continue to explore the epithermal gold deposits in this range; if both contribute to placer gold, the rock-gold mineralization zone The formation type is epigenetic low-temperature hydrothermal gold deposit-porphyry copper-gold composite gold deposit, which indicates that at least part of the epigenetic low-temperature hydrothermal gold deposit has been denuded deeply. Continue to explore epigenetic low-temperature hydrothermal gold deposits and porphyry copper-gold deposits in the mineralized area to provide reference for subsequent exploration work.

Compared with the prior art, the prospecting method based on placer gold pointer mineralogy provided in this embodiment utilizes the amount of placer gold in the water system sediments + placer gold mineralogy + placer gold geochemistry + geophysical prospecting method to explore the hidden porphyry-shallow formation in the thick coverage area. For low-temperature hydrothermal deposits, the favorable porphyry-epihydrothermal mineralization area is selected as the area to be explored according to the geological metallogenic law and combined with the existing regional geological data. Google Earth and GlobalMapper software are used in combination with artificial visual terrain. The geomorphological method extracts and delineates the water system and catchment basin in the selected area to be explored, and then measures the natural heavy sand of the water system according to the distribution of the water system in the to-be-explored area and the catchment basin, and determines the abnormal amount of placer gold in the catchment basin, and then determines the abnormal amount of placer gold in the catchment basin. The quantitative distribution sequence, mineralogical and geochemical characteristic distribution maps of placer gold are used in the catchment basin to delineate the rock gold mineralization area independently or after being superimposed in sequence, and further determine the mineralization type of the rock gold mineralization area by the geochemical characteristic parameters of placer gold. , the mineralization type of the rock-gold mineralized area is used as the basis for geophysical exploration verification in the delineated rock-gold mineralized area; The delineated rock gold mineralization area is delineated by the audio magnetotelluric method to delineate the low-resistance mineralization alteration zone, which can further narrow the prospecting target area and provide a basis for better arrangement of drilling projects, avoid blindly carrying out geophysical exploration and drilling work, and reduce exploration drilling. It greatly reduces the exploration cost and significantly improves the exploration efficiency of gold deposits in the strong denudation and thick coverage area.

Example 3

In yet another specific embodiment of the present invention, the prospecting method of Embodiment 1 is used to conduct porphyry-epithermal low-temperature ore deposit exploration in the Duolong super-large porphyry-epithermal copper-gold ore concentration area in Tibet. On the basis of research results and field geological surveys, not only the distribution and variation laws of placer gold quantity and morphology at different locations have been identified, but also the mineralogy of placer gold produced by porphyry-high-sulfur epithermal deposits with different degrees of denudation. The identification method of the mineralization center was constructed, and the mineralization center (rock-gold mineralization area) of each deposit in the Duolong copper-gold ore concentration area was successfully delineated.

The controlled copper resources in the Duolong ore concentration area exceed 20 million tons, the associated gold exceeds 400 tons, and the prospective copper resources can reach more than 30 million tons, and a typical porphyry-epigenetic low-temperature metallogenic system is developed. Porphyry-type and epigenetic low-temperature hydrothermal deposits have a large scale of mineralization, and are also well-known placer gold producing areas.

In this example, the topographical features of the Duolong ore concentration area were obtained by using the 91 satellite map assistant and Global Mapper software, and the water systems developed in the Duolong ore concentration area were extracted and the catchment basins were delineated to obtain the The distribution map of the water system and catchment basin is shown in Figure 5. On the distribution map of the water system and catchment basin in the Duolong ore concentration area, the sampling points are designed in different regions, and the layout map of the sampling points in the Duolong ore concentration area is obtained. Deploy sampling at 500-meter sampling intervals in the near-mine areas of Tiegelongnan, Naruo, Duobuza, Gaerqin and Bunker-Namugang deposits, and sparse to 2,000 meters at the periphery of the water system; , Tiegeshan, Nadun, Saijiao, and Sena ore deposits are deployed with sampling points with a spacing of 1,000 meters; in the Duolong ore concentration area, the sampling objects are water system sediments and broken deposits in the near-mine area, and a single group of samples is collected. The weight is 12-15Kg, and a total of 230 groups of samples to be processed are collected, of which 30 groups are repeated point sampling, and the sampling quality and representativeness are strictly controlled.

The collected samples to be processed are naturally dried. A single group of samples is uniformly weighed 10kg. After screening, the sample particles with a particle size of less than 8mm enter the placer gold selection process, and the particles below 2mm are selected for preliminary sorting. Feldspar and other light mineral tailings, the coarse concentrate is again naturally air-dried; magnetite, pyrrhotite, limonite, ilmenite, pyroxene, amphibole, etc. are eliminated through magnetic separation and electromagnetic separation. Heavy liquid (CHBr ₃ ) was separated to obtain heavy minerals with a specific gravity greater than 2.8, and the target placer gold particles were selected under binoculars.

The number of placer gold particles is counted according to the particle size, and the catchment basin with abnormal quantity of placer gold is determined. Combined with the location coordinate information of the sampling point, the distribution map of the water system and catchment basin in the Duolong ore concentration area or the layout map of the sampling point is further developed. Draw a sequence distribution map of placer gold quantity distribution in the Duolong ore concentration area. Based on the relationship between the spatial distribution of placer gold shown by the placer gold quantity distribution sequence distribution map and the Duolong porphyry-epigenetic low-temperature hydrothermal deposit, delineate a number of places in the Duolong ore concentration area. The mineralization center, as shown in Figure 6.

The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited to this. Substitutions should be covered within the protection scope of the present invention.

Claims (14)

1. A kind of prospecting method based on placer gold pointer mineralogy, is characterized in that, comprises the steps:

   Based on the topographic features of the to-be-explored area, extract the water system in the to-be-explored area and delineate and divide the catchment basin, and obtain the distribution map of the water system and the catchment basin in the to-be-explored area;

   In the water system distribution of the area to be explored and the limited range of the catchment basin, the natural heavy sand measurement of the water system is carried out to obtain the placer gold in a single set of samples;

   According to the amount of placer gold in a single set of samples, determine the catchment basins with abnormal quantity of placer gold, and draw the distribution map of abnormal grades of placer gold in the catchment basin on the basis of the distribution map of water system and catchment basin in the area to be explored;

   On the basis of the distribution map of placer gold anomaly grades in the catchment basin, using the quantity characteristics of placer gold to draw the sequence map of placer gold quantity distribution and delineate the rock gold mineralization area.
2. The ore prospecting method based on placer gold pointer mineralogy according to claim 1, wherein the characteristic distribution map of placer gold morphological groups is drawn by using the mineral morphological characteristics of placer gold, and the rock gold mineralization area is delineated.
3. The ore prospecting method based on placer gold pointer mineralogy according to claim 2, wherein the drawing of the placer gold morphological group characteristic distribution map comprises the steps of: dividing the placer gold morphological group types according to the placer gold morphological characteristics, and counting a single group of samples The proportion of all types of morphological groups of gold placer, based on the sequence diagram of the number distribution of gold placer, map the morphological group type characteristics of placer gold, and obtain the distribution map of morphological group type characteristics of placer gold.
4. The ore prospecting method based on placer gold pointer mineralogy according to claim 3, wherein the principle of drawing placer gold quantity distribution sequence and delineating rock gold mineralization area by utilizing the quantitative characteristics of placer gold is: the closer to the rock gold mineralization center , the higher the placer gold quantity grade; the farther away from the rock gold mineralization center, the lower the placer gold quantity grade;

   The types of placer gold morphological groups include primitive type, reformed type and remodeling type. The principle of using the characteristics of placer gold morphological groups to draw the distribution map of placer gold morphological groups and delineate the rock gold mineralization area is: the closer to the rock gold mineralization center, the more The greater the proportion of the original and transformed forms of placer gold.
5. The prospecting method based on placer gold pointer mineralogy according to any one of claims 1 to 4, characterized in that, extracting the water system in the area to be explored and delineating and dividing the catchment basins include the following steps: Automatically extracting the area to be explored by using software The water system data is automatically delineated and divided into the catchment basins, and the water system and catchment basins in the exploration area are supplemented, extracted, corrected and revised in combination with the artificial visual topography and geomorphology method.
6. The ore prospecting method based on placer gold pointer mineralogy according to any one of claims 1 to 4, characterized in that, carrying out water system natural heavy sand measurement, and obtaining the placer gold in a single group of samples comprises the following steps:

   Arrange sampling points on the distribution map of the water system and catchment basin in the area to be explored, and draw the sampling point layout map;

   Collect samples to be processed at the set sampling points under GPS track monitoring;

   The collected samples to be processed are processed to obtain placer gold in multiple single groups of samples.
7. The ore prospecting method based on placer gold pointer mineralogy according to claim 6, characterized in that, processing the collected samples to be processed, and obtaining the placer gold in a plurality of single-group samples comprises the following steps:

   The multiple groups of samples to be treated collected from the field were naturally air-dried, combed repeatedly with a wooden comb and mixed evenly, and the multiple groups of samples to be treated were weighed with the same weight to obtain multiple single-group samples;

   Multiple single groups of samples are screened with cylindrical sieves to separate the gravel and sediment, and the sand and mud parts under the sieve of a single group of samples are subjected to rough elutriation, magnetic separation, electromagnetic separation, fine elutriation, and heavy liquid separation. And binocular identification and selection, to get multiple single-group samples of placer gold.
8. The ore prospecting method based on placer gold pointer mineralogy according to claim 7, is characterized in that, determining the catchment basin with abnormal quantity of placer gold comprises the steps of: grading the catchment basin according to the quantity abundance of placer gold in the catchment basin;

   The formula for calculating the abundance of placer gold is:

   R=N/(n×m),

   Among them, R is the abundance of placer gold; N is the total number of placer gold produced in a single catchment basin; n is the total number of sample groups in a single catchment basin; m is the weight of a single group of samples.
9. The ore prospecting method based on placer gold pointer mineralogy according to any one of claims 1 to 4, 7 to 8, is characterized in that, after determining the abnormal catchment basin of placer gold quantity, it also comprises the following steps:

   In a catchment basin with an abnormal amount of placer gold, the transportation distance of placer gold and the suspected rock-gold mineralization area are preliminarily estimated by using the roundness, sorting and composition of the gravel group associated with placer gold, and the suspected rock-gold mineralization area is preliminarily delineated; The principle is:

   The higher the proportion of wear-resistant components in the gravel, the better the roundness and sorting, and the longer the transport distance of placer gold; the lower the proportion of wear-resistant components in the gravel, the better the roundness and sorting. The worse the property is, the closer the placer gold is transported.
10. The ore prospecting method based on placer gold pointer mineralogy according to any one of claims 1 to 4, 7 to 8, characterized in that, after delineating the rock gold mineralization zone, the method further comprises the following steps:

    On the basis of the distribution map of placer gold anomaly grades in the catchment basin, the mineralogical characteristics of placer gold are used to delineate the rock gold mineralization area and narrow the scope of the prospecting target area.
11. The ore prospecting method based on placer gold pointer mineralogy according to claim 10, is characterized in that, utilizing the mineralogy of placer gold to delineate the rock gold mineralized area, and narrowing the scope of the prospecting target area comprises the following steps:

    Scanning electron microscope was used to observe the standard round target of placer gold epoxy resin, and the mineralogy characteristics of placer gold core were statistically analyzed. , draw the mineralogical characteristics distribution map of the placer gold core, delineate the rock gold mineralization area, and narrow the scope of the prospecting target area.
12. The ore prospecting method based on placer gold pointer mineralogy according to any one of claims 1 to 4, 7 to 8, and 11, characterized in that, after delineating the rock gold mineralization zone, the method further comprises the following steps:

    Exploration is carried out in the delineated rock-gold mineralization area by using the geophysical method, and the scope of the prospecting target area is narrowed.
13. The ore prospecting method based on placer gold pointer mineralogy according to claim 12, characterized in that, before using the geophysical prospecting method to explore the results of the delineated rock gold mineralization area, the geochemical characteristics of placer gold are used to discriminate the preliminarily delineated rock gold. type of mineralization in the mineralized zone;

    The mineralization type of the rock-gold mineralized area is used as the basis for geophysical verification in the delineated rock-gold mineralized area.
14. The ore prospecting method based on placer gold pointer mineralogy according to claim 13, wherein the mineralization type of the rock-gold mineralization zone includes epigenetic low-temperature hydrothermal gold deposits, porphyry copper-gold deposits or epigenetic low-temperature hydrothermal deposits There are three types of gold-porphyry copper-gold composite gold deposits;

    If the mineralization type of the rock-gold mineralization area is an epithermal gold deposit with low temperature, the geophysical prospecting or drilling method shall be adopted in the delineated rock-gold mineralization area to continue to explore the porphyry copper-gold deposit;

    If the mineralization type of the rock-gold mineralization area is a porphyry copper-gold deposit, it is not necessary to continue to explore the epigenetic low-temperature hydrothermal gold deposit in the delineated rock-gold mineralization area;

    If the mineralization type of the rock-gold mineralization area is an epigenetic low-temperature hydrothermal gold ore-porphyry-type copper-gold complex gold deposit, the epigenetic low-temperature thermal exploration should be continued in the delineated rock-gold mineralization area in combination with other geological data as the case may be. Liquid gold deposits and porphyry copper-gold deposits.

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