Waste pyrite well acid heavy metal drainage plugging process and structure thereof

Abstract

The present application relates to the technical field of mine tunnel acid water pollution treatment, and discloses a kind of abandoned pyrite well acid heavy metal drainage plugging process and its structure, and its specific steps include:1) tunnel hydrogeological survey: according to the position of water seepage point and the size of water seepage amount, tunnel is divided into gushing area, water leaching area and dry area;2) division of grouting plugging area and complete surrounding rock impermeable area: divided into grouting plugging area and complete surrounding rock impermeable area;3) configuration of plugging material: configuration of modified acid-resistant ultra-fine cement, bentonite;4) plugging tunnel: by high-pressure grouting equipment, modified acid-resistant ultra-fine cement is injected into grouting plugging area, and bentonite is backfilled to complete surrounding rock impermeable area.The present application sets up specific plugging structure for mine gushing channel through the backfilling of abandoned pyrite well, to a certain extent, reduces the generation amount of acid heavy metal drainage, and realizes the purpose of acid heavy metal drainage reduction of abandoned pyrite well.

Description

Technical Field

[0001] This invention relates to the field of acidic water mine tunnel pollution control technology, and in particular to a process and structure for sealing acidic heavy metal drainage in abandoned pyrite mines. Background Technology

[0002] During underground pyrite mining, high-sulfur ore is extracted, leaving behind a significant amount of low-sulfur pyrite ore around the mine. These sulfur-containing minerals dissolve and oxidize to form acidic heavy metals in the wastewater, which has a serious adverse impact on the downstream surface water environment.

[0003] Located within metamorphic rocks, pyrite is influenced by several hydrogeological factors affecting groundwater occurrence and transport. These factors primarily include bedrock joints and fracture zones, and fault fracture zones. The development of bedrock joints and fracture zones, along with the permeability of these zones, significantly impacts the overall permeability distribution within the pyrite deposit. Areas with underdeveloped bedrock joints or impermeable fault fracture zones are generally drier; conversely, areas with well-developed bedrock joints or water-conducting fault fracture zones typically experience higher permeability. Therefore, sealing measures for acidic heavy metal drainage in mines must be tailored to the specific permeability levels. Furthermore, considering the acidic environment of mines, sealing materials must also possess acid resistance to enhance their long-term stability.

[0004] Therefore, the present invention provides a drainage and plugging structure for acidic heavy metals in abandoned pyrite mines, including corresponding acid-resistant plugging materials, to solve the above-mentioned technical problems. Summary of the Invention

[0005] This invention addresses the shortcomings of existing technologies by providing a process and structure for sealing acidic heavy metal drainage in abandoned pyrite mines.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] A process for sealing acidic heavy metal drainage in abandoned pyrite mines, comprising the following steps:

[0008] 1) Tunnel hydrogeological survey: Pyrite is located in metamorphic rock and forms tunnels after excavation. During the tunnel hydrogeological survey, seepage parameters are measured and recorded. Seepage parameters include the location of seepage points and the amount of seepage. Based on the location of seepage points and the amount of seepage, the tunnel is divided into water-bearing areas, water-sprinkling areas and dry areas.

[0009] 2) Division of grouting sealing zone and intact surrounding rock seepage prevention zone: Based on the degree of bedrock fracture, the tunnel surrounding rock is divided into fault fracture zone, bedrock fissure development zone and intact bedrock zone. The fault fracture zone and bedrock fissure development zone are jointly divided into grouting sealing zone, and the intact bedrock zone is divided into intact surrounding rock seepage prevention zone.

[0010] 3) Preparation of sealing materials: Preparation of modified acid-resistant ultrafine cement and bentonite;

[0011] 4) Sealing the tunnel: Modified acid-resistant ultrafine cement is injected into the upper part of the grouting and sealing area using high-pressure grouting equipment, and bentonite is backfilled to the bottom of the intact surrounding rock seepage prevention zone.

[0012] As a preferred option, the preparation of modified acid-resistant ultrafine cement involves adding 20%-30% by mass of volcanic ash to the ultrafine cement for modification. The active components of silica and alumina contained in the volcanic ash react with the cement hydration product calcium hydroxide to produce hydrated calcium silicate and hydrated calcium aluminate with good chemical stability.

[0013] Preferably, the area of ​​the grouting sealing zone is less than 5-10m². 2 This area is defined as a small-area grouting and sealing zone, and bentonite is backfilled at the bottom of the small-area grouting and sealing zone.

[0014] Preferably, the cross-sectional area of ​​the grouting sealing zone is greater than or equal to 5-10 m². 2 It is defined as a large-area grouting and sealing area. In step 3), it is also necessary to prepare a mixture of acid-resistant cement and lead-zinc tailings. In step 4), the mixture of acid-resistant cement and lead-zinc tailings is backfilled to the bottom of the large-area grouting and sealing area using high-pressure grouting equipment.

[0015] As a preferred option, the preparation of a mixture of acid-resistant cement and lead-zinc tailings involves: modifying ordinary cement by adding 20%-30% by mass of volcanic ash to form acid-resistant cement, and then adding lead-zinc tailings into the acid-resistant cement.

[0016] Preferably, the sulfur content in lead-zinc tailings must be less than 5%.

[0017] Preferably, the mass ratio of acid-resistant cement to lead-zinc tailings is between 1:6 and 1:10.

[0018] Preferably, the seepage zone is defined as a continuous flow of water, with a flow rate greater than 0.05 L / (m³). 2 •s); When the water is dripping intermittently, it is considered a water-spraying zone, with a flow rate of 0.005-0.05 L / (m³). 2 The dry zone is defined as the area between 0.005 L / (m³) and 0.005 L / (m³). The flow rate is less than 0.005 L / (m³). 2 ·s).

[0019] As a preferred option, the bedrock fracture degree parameter is the bedrock fissure rate, where the rock near the fault fracture zone is fractured with a fissure rate greater than 5%, and the water-bearing zone corresponds to the fault fracture zone; the bedrock fissure development zone has a fissure rate between 2-5%, and the water-bearing zone corresponds to the bedrock fissure development zone; the intact bedrock zone has a fissure rate of less than 2%, and the dry zone corresponds to the intact bedrock zone.

[0020] Preferably, the pressure generated by the high-pressure grouting equipment in step 4) is 25-35 MPa.

[0021] A drainage and sealing structure for acidic heavy metals in abandoned pyrite mines includes a grouting sealing zone and a intact surrounding rock seepage prevention zone. The intact surrounding rock seepage prevention zone is filled with bentonite. The grouting sealing zone is divided into sections with a cross-sectional area of ​​less than 5-10 m². 2 Small-area grouting sealing areas and cross-sectional areas greater than or equal to 5-10m² 2 The large-area grouting sealing area is filled with modified acid-resistant ultrafine cement at the top and bentonite at the bottom. The large-area grouting sealing area is filled with modified acid-resistant ultrafine cement at the top and a mixture of acid-resistant cement and lead-zinc tailings at the bottom.

[0022] The present invention has significant technical effects due to the adoption of the above technical solutions: the present invention reduces the amount of acid heavy metal drainage to a certain extent by backfilling abandoned pyrite mines and setting targeted sealing structures for the mine water inflow channels, thereby achieving the purpose of reducing the amount of acid heavy metal drainage from abandoned pyrite mines. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the present invention.

[0024] The locations indicated by the numbers in the attached diagram are as follows: 1—grouting and sealing area, 2—intact surrounding rock seepage prevention area, 3—modified acid-resistant ultrafine cement, 4—bentonite, 5—acid-resistant cement mixed with lead-zinc tailings, 11—small area grouting and sealing area, 12—large area grouting and sealing area. Detailed Implementation

[0025] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0026] Example 1

[0027] A process for sealing acidic heavy metal drainage in abandoned pyrite mines, comprising the following steps:

[0028] 1) Tunnel hydrogeological survey: Pyrite is located in metamorphic rock and forms tunnels after excavation. During the tunnel hydrogeological survey, seepage parameters are measured and recorded. Seepage parameters include the location of seepage points and the amount of seepage. Based on the location of seepage points and the amount of seepage, the tunnel is divided into water-bearing areas, water-sprinkling areas and dry areas.

[0029] 2) Division of Grouting and Sealing Zone 1 and Intact Bedrock Seepage Prevention Zone 2: Based on the degree of bedrock fracture, the tunnel surrounding rock is divided into fault fracture zone, bedrock fissure development zone, and intact bedrock zone. Under normal circumstances, the fault fracture zone has a large seepage volume and is a water inrush zone; the bedrock fissure development zone is a dripping zone and is a water sprinkling zone; while the intact bedrock zone is a dry zone. The fault fracture zone and the bedrock fissure development zone are jointly divided into grouting and sealing zone 1, and the intact bedrock zone is divided into intact bedrock seepage prevention zone 2.

[0030] 3) Prepare sealing materials: Prepare modified acid-resistant ultrafine cement 3 and bentonite 4;

[0031] 4) Sealing the tunnel: Modified acid-resistant ultrafine cement 3 is injected into the upper part of the grouting sealing area 1 through high-pressure grouting equipment. The ultrafine cement particles of modified acid-resistant ultrafine cement 3 are very fine, and the rheological controllability of the grout is good, which is conducive to the diffusion of the grout. It can diffuse to the small cracks in the rock strata, resulting in good sealing effect and high water blocking efficiency. The intact surrounding rock seepage prevention area 2 is a complete surrounding rock of the mine with undeveloped bedrock joints and fissures, and almost no dripping or seepage. Bentonite 4 is used as the mine filling material. Therefore, bentonite 4 is backfilled to the bottom of the intact surrounding rock seepage prevention area 2.

[0032] Preparation of modified acid-resistant ultrafine cement 3: Mine drainage is highly acidic, with a pH generally between 2 and 4. Ordinary ultrafine cement has poor stability in acidic environments. By adding 20%-30% by mass of volcanic ash to ultrafine cement for modification, the active components of silica and alumina contained in the volcanic ash react with the cement hydration product calcium hydroxide to produce hydrated calcium silicate and hydrated calcium aluminate with good chemical stability. This enhances the acid erosion resistance of ultrafine cement, thereby increasing stability and reducing permeability, thus enhancing the acid erosion resistance of cement.

[0033] When the seepage exhibits a continuous flow, it is considered a water inrush zone, with an inrush rate greater than 0.05 L / (m²). 2 •s); When the water is dripping intermittently, it is considered a water-spraying zone, with a flow rate of 0.005-0.05 L / (m³). 2 The dry zone is defined as the area between 0.005 L / (m³) and 0.005 L / (m³). The flow rate is less than 0.005 L / (m³). 2 ·s).

[0034] The parameter for the degree of bedrock fracture is the bedrock fissure rate. Among them, the rock near the fault fracture zone is fractured with a fissure rate greater than 5%, and the water-bearing area generally corresponds to the fault fracture zone; the fissure rate of the bedrock fissure development zone is between 2-5%, and the water-bearing area generally corresponds to the bedrock fissure development zone; the fissure rate of the intact bedrock area is less than 2%, and the dry area generally corresponds to the intact bedrock area.

[0035] The pressure generated by the high-pressure grouting equipment in step 4) is 25-35 MPa.

[0036] Example 2

[0037] Similar to Example 1, except that the area of ​​the grouting sealing zone 1 is less than 8m². 2 It is defined as a small-area grouting and sealing zone 11, and bentonite 4 is backfilled at the bottom of the small-area grouting and sealing zone 11.

[0038] Example 3

[0039] Similar to Example 2, except that the cross-sectional area of ​​the grouting sealing zone 1 is greater than or equal to 8m². 2 This area is defined as a large-area grouting and sealing zone 12. This area usually has a large amount of water seepage and poor surrounding rock stability, making it prone to collapse. In addition to the grouting and sealing described in Example 1, the large-area grouting and sealing zone 12 also needs to maintain its stability and prevent collapse through mine filling. Therefore, in step 3), it is also necessary to prepare a mixture 5 of acid-resistant cement and lead-zinc tailings. In step 4), the mixture 5 of acid-resistant cement and lead-zinc tailings is backfilled to the bottom of the large-area grouting and sealing zone 12 using high-pressure grouting equipment.

[0040] Preparation of acid-resistant cement mixed with lead-zinc tailings 5: This is not ultrafine acid-resistant cement. Ordinary cement is modified by adding 20%-30% volcanic ash by mass to form acid-resistant cement. In the unstable large-area grouting and sealing zone 12 (surrounding rock fracture zone), in order to increase the compressive strength of the mine sealing material and reduce the cost of the sealing material, lead-zinc tailings are added to the acid-resistant cement.

[0041] The sulfur content in lead-zinc tailings must be less than 5%.

[0042] The mass ratio of acid-resistant cement to lead-zinc tailings is between 1:6 and 1:10.

[0043] By grouting modified acid-resistant ultrafine cement 3 into the small-area grouting sealing zone 11 (fault fracture zone and bedrock fissure development zone) and backfilling the mine with a mixture of acid-resistant cement and lead-zinc tailings 5 ​​into the unstable large-area grouting sealing zone 12 (surrounding rock fracture zone), most of the acidic heavy metal drainage is controlled, and a small portion of the acidic heavy metal drainage is sealed by backfilling bentonite 4 into the intact bedrock zone, thus achieving the control of acidic drainage in the entire mining area.

[0044] Example 4

[0045] A drainage and sealing structure for acidic heavy metals in an abandoned pyrite mine includes a grouting sealing zone 1 and a intact surrounding rock seepage prevention zone 2 located within the mine. The intact surrounding rock seepage prevention zone 2 is filled with bentonite 4. The grouting sealing zone 1 is divided into sections with a cross-sectional area of ​​less than 8m². 2 Small-area grouting sealing area 11 and cross-sectional area greater than or equal to 8m² 2 The large-area grouting sealing area 12 and the small-area grouting sealing area 11 are filled with modified acid-resistant ultrafine cement 3 at the top and bentonite 4 at the bottom. The large-area grouting sealing area 12 is filled with modified acid-resistant ultrafine cement 3 at the top and a mixture of acid-resistant cement and lead-zinc tailings 5 ​​at the bottom.

[0046] In summary, the above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be covered by the present invention.

Claims

1. A process for sealing acidic heavy metal drainage in abandoned pyrite mines, characterized in that: The specific steps include: Tunnel hydrogeological survey: Pyrite is located in metamorphic rock and forms tunnels after excavation. During the tunnel hydrogeological survey, seepage parameters are measured and recorded. Seepage parameters include the location of seepage points and the amount of seepage. Based on the location of seepage points and the amount of seepage, the tunnel is divided into water-bearing areas, water-sprinkling areas and dry areas. Division of grouting sealing zone (1) and intact surrounding rock seepage prevention zone (2): Based on the degree of bedrock fracture, the tunnel surrounding rock is divided into fault fracture zone, bedrock fissure development zone and intact bedrock zone. The fault fracture zone and bedrock fissure development zone are jointly divided into grouting sealing zone (1), and the intact bedrock zone is divided into intact surrounding rock seepage prevention zone (2). Preparing sealing materials: preparing modified acid-resistant ultrafine cement (3) and bentonite (4); Sealing the tunnel: Modified acid-resistant ultrafine cement (3) is injected into the upper part of the grouting sealing area (1) through high-pressure grouting equipment, and bentonite (4) is backfilled to the bottom of the intact surrounding rock seepage prevention area (2); The modified acid-resistant ultrafine cement (3) is prepared by adding 20%-30% volcanic ash by mass to ultrafine cement to modify it; The cross-sectional area of ​​the grouting sealing zone (1) is greater than or equal to 8m². 2 It is defined as a large-area grouting and sealing area (12). In the preparation of sealing materials, it is also necessary to prepare a mixture of acid-resistant cement and lead-zinc tailings (5). In the sealing tunnel, the mixture of acid-resistant cement and lead-zinc tailings (5) is backfilled to the bottom of the large-area grouting and sealing area (12) by high-pressure grouting equipment. The mixture of acid-resistant cement and lead-zinc tailings (5) is prepared by adding 20%-30% volcanic ash by mass to ordinary cement to modify the cement and form acid-resistant cement. Lead-zinc tailings are added to the acid-resistant cement. The sulfur content in the lead-zinc tailings must be less than 5%. The mass ratio of acid-resistant cement to lead-zinc tailings is between 1:6 and 1:

10. The area of ​​the grouting and sealing area (1) is less than 8m². 2 It is then defined as a small-area grouting and sealing zone (11), and bentonite (4) is backfilled at the bottom of the small-area grouting and sealing zone (11).

2. The acidic heavy metal drainage and plugging process for abandoned pyrite mines according to claim 1, characterized in that: When the seepage exhibits a continuous flow, it is considered a water inrush zone, with an inrush rate greater than 0.05 L / (m³). 2 •s); When the water is dripping intermittently, it is considered a water-sprinkling zone, with a flow rate of 0.005-0.05 L / (m³). 2 The dry zone is defined as the area between 0.005 L / (m³) and 0.005 L / (m³). The flow rate is less than 0.005 L / (m³). 2 ·s).

3. The acidic heavy metal drainage sealing process for abandoned pyrite mines according to claim 1, characterized in that: The bedrock fracture degree parameter is the bedrock fissure rate. Among them, the rock near the fault fracture zone is fractured with a fissure rate greater than 5%, and the water-bearing area corresponds to the fault fracture zone; the bedrock fissure development zone has a fissure rate between 2-5%, and the water-bearing area corresponds to the bedrock fissure development zone; the intact bedrock area has a fissure rate of less than 2%, and the dry area corresponds to the intact bedrock area.

4. The acidic heavy metal drainage sealing process for abandoned pyrite mines according to claim 1, characterized in that: The pressure generated by the high-pressure grouting equipment in the process of sealing the tunnel is 25-35 MPa.

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