GB 50863-2013Code for design of tailings facilities (English PDF)

2.0.1 Tailings pond

It is used to store metal and non-metal mines for ore sorting and discharge tailings.

2.0.2 Whole storage capacity

The volume of the space enclosed below the dam crest level and above the bottom of the reservoir (excluding the volume of the dam not constructed of tailings).

2.0.3 Effective storage capacity effective storage capacity

The space volume below the sedimentary beach surface and above the bottom of the reservoir for storing tailings (including suspended tailings slurry).

2.0.4 Flood regulation storage capacity

The volume above the normal water level and below the design flood level that can accumulate flood.

2.0.5 Total storage capacity

The full storage capacity at which the final crest elevation is designed.

2.0.6 Tailings dam

Outer structures of tailings ponds that block tailings and water. It usually refers to the whole of initial dam and tailings accumulation dam.

2.0.7 Starter dam

It is a dam built with soil, stone materials, etc., as the drainage or support body of the tailings accumulation dam.

2.0.8 Tailings accumulation dam embankment

The dam formed by the accumulation of tailings during the production process.

2.0.9 Upstream embankment method

The dam construction method of accumulating tailings in the upstream direction of the initial dam is characterized in that the axis of the accumulation dam crest moves to the upstream direction of the initial dam step by step.

2.0.10 Centerline embankment method

The cyclone is used to separate the coarse tailing sand at the initial dam axis, and its characteristic is that the axis of the dam crest remains unchanged.

2.0.11 Downstream embankment method

In the downstream direction of the initial dam, the cyclone is used to separate the coarse tailings to construct the dam, which is characterized in that the axis of the accumulation dam crest moves to the downstream direction of the initial dam step by step.

2.0.12 Phreatic line

The position of the free surface of seepage water in the dam body, which is a curve on the cross section.

2.0.13 Critical position of the phreatic line

It refers to the wetting line of the dam body when the anti-sliding stability safety factor of the dam body can meet the minimum requirements of this code.

2.0.14 Controlled position of the phreatic line

The maximum infiltration line of the dam body that meets the requirements of the critical infiltration line and the minimum burial depth infiltration line in the downstream slope of the tailings accumulation dam.

2.0.15 Normal production level nonmal production level

The water level in the tailings pond that can meet the production backwater and discharge requirements.

2.0.16 Deposited beach

The surface layer of the sedimentary body formed by hydraulic alluvial tailings is divided into two parts. above water and below water according to the water surface of the catchment area in the reservoir.

2.0.17 Beach crest

The intersection of the sedimentary beach and the outer slope of the sub-dam.

2.0.18 Beach width

The horizontal distance from the water edge in the library to the top of the beach.

2.0.19 Safe super high free height

Under non-earthquake operating conditions, the tailings accumulation dam is the height difference between the beach top elevation and the design flood level; the retaining dam and the one-time damming tailings dam are the sum of the design flood level plus the maximum wave rise and the maximum wind-backed water level The height difference from the dam crest level. Under seismic operating conditions, the tailings accumulation dam is the height difference between the beach top elevation and the normal production water level plus the sum of seismic settlement and seismic choke height; the retaining dam and one-time damming tailings dam are the normal production water level plus the maximum wave climb height, the height difference between the sum of the maximum wind-backed water surface height, seismic settlement and seismic backwater height, and the dam crest elevation.

2.0.20 Flood regulation height

Refers to the height difference between the initial water level of normal flood discharge and the design flood level.

2.0.21 Tailings dam height tailings dam height

Upstream dam construction refers to the height difference between the crest of the accumulation dam and the original ground at the initial dam axis; midline and downstream dam construction refers to the height difference between the dam crest and the original ground at the dam axis.

2.0.22 Total dam height total dam height

The dam height at which the final stacking elevation is designed.

2.0.23 Embankment height or accumulation height

The upstream tailings dam is the height difference between the tailings accumulation dam crest and the initial dam crest; the midline and downstream tailings dams are the height difference between the tailings accumulation dam crest and the original ground at the axis of the dam crest.

2.0.24 Water dam of tailings pond

The dam body that retains water for a long time or longer period often refers to the main dam and auxiliary dam without tailings dam.

2.0.25 Length of tailings pond

The distance from the top of the beach (the dam axis for the initial dam) to the farthest waterside of the tailings pond along the vertical direction of the dam axis; distance.

2.0.26 One-step constructed dam

Refers to the tailings dam constructed in one go or in stages using all damming materials other than tailings.

3.1 Site selection

3.1.1 Tailings ponds should not be located in the following areas.

1 Scenic spots, nature reserves, drinking water source protection areas;

2 Mineral mining areas prohibited by national law.

3.1.2 The site selection of the tailings pond shall be comprehensively determined through technical and economic comparison of multiple schemes, and shall meet the following requirements.

1 It is not suitable to be located in the upstream of large industrial and mining enterprises, large water sources, important railways and highways, aquatic bases and large residential areas;

2 It should not be located on the windward side of the dominant wind direction in residential areas;

3 No or less farmland should be occupied, and no or less residents should be relocated;

4.It is not suitable to be located on the valuable ore deposit;

5 The catchment area should be small and have sufficient storage capacity;

6 The upstream wet tailings pond should have sufficient initial and final lengths;

7 The amount of dam construction should be small, and the production management should be convenient;

8.Areas with complex geological structures and severe adverse geological phenomena should be avoided;

9 The conveying distance of tailings should be short, self-flowing or with small head.

3.1.3 When two or more tailings ponds are built in the same valley, the mutual relationship and influence between each tailings pond should be fully demonstrated during the subsequent design of the ponds.

3.1.4 When tailings are stored in abandoned open pits and depressions, a special safety demonstration should be conducted; when there is mining activity in the lower part of the open pit, tailings should not be stored.

3.2 Storage capacity

3.2.1 The required effective storage capacity of the tailings pond should be determined according to the following formula.

In the formula. V - the effective storage capacity of the required tailings pond (m3);

W——the amount of tailings to be stored within the design life of the tailings pond (t);

rhod—the average bulk dry density of tailings in the tailings pool (t/m3).

3.2.2 The average bulk dry density of tailings in the tailings pond should be determined according to the test or the measured data of similar tailings ponds; when there is a lack of data, the hydraulic alluvial tailings with tailings particle density rhog of 2.7t/m3 can be determined according to the table 3.2.2 Selected; for tailings with other densities, the values in Table 3.2.2 should be multiplied by the correction factor beta. The beta value can be determined according to the following formula.

Table 3.2.2 Average bulk dry density of tailings (t/m3)

Note. Original tailings refers to the tailings discharged from the concentrator without natural or mechanical classification; the definition of the name of the original tailings is determined in accordance with Appendix A of this specification.

3.2.3 The effective storage capacity and flood control storage capacity of the tailings reservoir shall be calculated and determined according to the sedimentary beach surface and reservoir bottom topography with different slopes of the tailings.

The slope it of the tailings sedimentary beach can be determined according to the physical properties of the tailings, the topography of the tailings pond and the ore-drawing conditions of other tailings ponds with similar ore-drawing conditions or determined by experiments. When there is a lack of data, it can be calculated according to Appendix B of this specification. When calculating the effective storage capacity, a larger value of 1.0it~1.2it can be taken, and a smaller value of 0.8it~1.0it can be taken when calculating the storage capacity for flood regulation.

3.3 Grades of tailings ponds and structures

3.3.1 The grade of the tailings pond shall be determined according to Table 3.3.1 according to the final full storage capacity of the tailings pond and the final dam height. The design grades of tailings ponds in each service period shall be determined according to Table 3.3.1 according to the full storage capacity and dam height of the period. When the grade difference of the tailings pond grade determined according to the full storage capacity of the tailings pond and the dam height is the first grade, the higher one shall prevail;.

When tailings are stored in open-air abandoned mining pits and depressions, and no tailings dams are built around them, the grade may not be determined; when tailings dams are built, the grades of tailings ponds should be determined according to the height of the dam and its corresponding storage capacity.

Except for first-class dams, for tailings dams whose accidents will cause serious disasters to important downstream towns, industrial and mining enterprises, main railway lines or expressways, etc., the design level can be raised to a first-class level after full demonstration.

Table 3.3.1 Design grades for each service period of tailings ponds

3.3.2 The grade of the tailings pond structure shall be determined according to Table 3.3.2 according to the grade and importance of the tailings pond.

Table 3.3.2 Grades of tailings pond structures

Note. 1 The main structures refer to structures that will cause downstream disasters after accidents, such as tailings dams and drainage structures;

2 Secondary structures refer to permanent structures other than the main structures;

3 Temporary structures refer to structures temporarily used during the construction period.

3.4 Monitoring facilities

3.4.1 The tailings pond should be equipped with necessary safety and environmental monitoring facilities according to the design grade, tailings dam construction method, nature of tailings and tailings water pollutants, topographic and geological conditions, and geographical environment. Third-class and above tailings ponds should be equipped with safety monitoring facilities that combine manual monitoring and automatic monitoring.

3.4.2 The selection of monitoring instruments and facilities should be reliable, durable, economical and applicable, and strive to be technologically advanced.

3.4.3 Safety monitoring items should include the following.

1 The water level of the wet discharge tailings pond, the elevation of the beach top, the length of the dry beach, the depth of the infiltration line, the slope and displacement of the dam body shall be monitored;

2 Rainfall should also be monitored for wet discharge tailings ponds of grade four and above; pore water pressure, seepage water volume and water quality should be monitored when necessary for wet discharge tailings ponds of grade three and above.

3.4.4 Safety monitoring facilities should be arranged according to the following principles.

1 It should fully reflect the operating status of the tailings pond;

2 The layout of tailings dam displacement monitoring points should extend to a certain range beyond the dam foot;

3 Monitoring facilities should be added to the dam abutment and bedrock fault zone, and the pipe buried in the dam.

3.4.5 Environmental monitoring items should include the following.

1 Monitoring the amount and composition of tailings entering the warehouse, and the water volume and composition of discharged tailings;

2 Water quality monitoring of tailings pond groundwater and surrounding water bodies.

3.4.6 The layout of environmental protection monitoring facilities should meet the requirements to reflect the operating conditions of the tailings pond.

3.5 Auxiliary facilities

3.5.1 Auxiliary facilities for tailings ponds should be equipped with damming machinery, working boats, engineering vehicles, traffic roads, duty rooms, emergency Facilities such as equipment storage, communication and lighting. If necessary, dormitories and simple meteorological and hydrological observation points in the reservoir area can be set up.

3.5.2 The duty room and dormitory of the tailings pond should avoid the downstream of the dam body.

4.1 General provisions

4.1.1 The selection of the tailings dam site should be based on the principles of small dam construction (heap) construction volume, large storage capacity and avoiding unfavorable engineering and hydrogeological conditions, combined with the source of dam construction materials, construction conditions, tailings clarification Factors such as distance and arrangement of drainage structures shall be determined through comprehensive demonstration.

4.1.2 The initial dam type selection shall meet the following requirements.

1 The initial dam should be constructed with local materials;

2 The initial dam of the upstream tailings pond should adopt the permeable dam type; the initial dam type of the midline and downstream tailings ponds can be determined according to the needs;

3 Tailings dams built at one time can be built in stages. The first phase dam should meet the relevant regulations of the initial dam, and the height of the later dam should always be greater than the tailings accumulation height requirements;

4 The impermeable dam type can be used for tailings ponds with special requirements.

4.1.3 The determination of the initial dam height shall meet the following requirements.

1 It can store at least the amount of tailings more than half a year after the concentrator is put into operation;

2 The tailings water should be clarified;

3 When the sedimentary beach top of the tailings accumulation dam is flush with the initial dam top, it shall meet the flood control standard requirements of the corresponding tailings pond;

4.When it is necessary to use the tailings pond to adjust and store water for production and supply in the initial stage of production, the required amount of adjusted and stored water should be stored;

5 In frozen areas, the requirements for ore discharge under ice shall be met;

6 The ratio of the initial dam height to the total dam height for a new upstream tailings dam should be 1/8 to 1/4.

4.1.4 The tailings dam must meet the requirements of seepage control and static and dynamic stability.

4.1.5 In case of the following situations, the foundation of the tailings dam should be specially studied and dealt with.

1 Sand and gravel foundation prone to tailings leakage;

2 Liquefiable soil, soft clay and collapsible loess foundation;

3 Karst development foundation;

4 Springs and mine shafts.

4.1.6 The choice of dam construction method for tailings accumulation dam shall meet the following requirements.

1 For areas with seismic fortification intensity of 7 degrees and below, upstream dam construction should be adopted; for areas with seismic fortification intensity of 8 to 9 degrees, downstream or midline dam construction should be adopted. Take anti-seismic measures;

2 For upstream tailings dam construction, the direct alluvial method can be used for dams with thicker tailings particles; the graded alluvial method should be used for dams with finer tailings particles;

3 The content of d>=0.074mm tailings particles used for dam construction after downstream or midline tailings grading should not be less than 75%, and the content of d<=0.02mm tailings particles should not be greater than 10%. When the tailings particles of the dam do not meet the above requirements, the dam building test shall be carried out. The rising speed of the dam should meet the requirements of the rising speed of the sedimentary beach;

4 When the tailings slurry weight concentration of the upstream dam exceeds 35% (excluding dry tailings), it is not suitable to use the alluvial method to build the dam directly;, tailings dam test research should be carried out;

5 For the wet tailings pond, when the whole tailings particles are extremely fine (d