RU2073790C1 - Method for underground leaching of minerals - Google Patents

Abstract

FIELD: mining industry. SUBSTANCE: method implies exposing of ore body by alternating rows of pumping-in and pumping-out boreholes, pumping in leaching solution and pumping out productive solution through respective boreholes. Pumping-in is started at maximal concentration of reagent in leaching solution which is maintained constant at initial period. Then concentration of reagent is continuously reduced according to mathematical relation taking into consideration shortest flow way of leaching solution between nearest pumping-in and pumping-in and pumping-out boreholes, filtering speed along shortest solution flow way, leaching period, preset time interval, permanent coefficient, and distance between boreholes in a row. EFFECT: high efficiency. 1 cl, 1 dwg

Description

 The invention relates to methods for extracting minerals (uranium, copper, rare earth and other metals) by underground leaching, which consists in feeding a leach solution to the ore body through a system of injection wells and extracting a productive solution containing useful product through pumping wells. The latter is then separated by sorption using ion exchange resins or other known methods. The processed solution is regenerated to the specified reagent content and is again pumped into the ore body.

 Known methods of underground leaching [1] These methods are safer and in some cases more economical than traditional methods of mining. However, the time-uncontrolled supply of the leach solution leads to an overrun of the reagent and the volume of the solution, as well as to a significant time change in the content of the useful product in the productive solution. This increases the cost of production and complicates the process of extracting a useful product.

 There are many known methods of underground leaching [2-5] (the last of which is adopted as a prototype), in which the injection and pumping of respectively leaching and productive solutions is carried out through a system of injection and pumping wells located in alternating linear rows. In this case, the parameters of the leach solution, mainly flow rate and high-quality composition, are regulated in time. However, the known regulatory methods cannot be considered effective, because they do not provide the necessary stabilization of the content of the useful product in the productive solution, reduce the consumption of reagent and solution volume, and increase the extraction of minerals.

 The aim of the invention is to increase productivity, efficiency and improve the environmental characteristics of the extraction of minerals by underground leaching.

где

;
l длина кратчайшей ленты тока выщелачивающего раствора между ближайшими закачной и откачной скважинами, м;
V_ф скорость фильтрации вдоль кратчайшей ленты тока раствора, м/сут,
τ_i=T_с+ndτ время, сут,
n = 1,2,3...dτ заданный временной интервал, сут,
К₁, К₂, К₃, К₄ постоянные коэффициенты, получаемые из уравнения (2) по результатам лабораторных исследований кернового материала, взятого из рудного тела, а при бурении скважин выдерживают соотношение:
l_i/b 1/7 1/8
где b расстояние между ближайшими рядами откачных и закачных скважин, l_i расстояние между ближайшими скважинами каждого ряда.This is achieved by the fact that the injection process begins with a maximum concentration of C (g / l) of the reagent in the leach solution, which is kept constant during the initial period T _c (day) in accordance with the dependence:

Where

;
l the length of the shortest current stream of the leaching solution between the nearest injection and pumping wells, m;
V _f the filtration rate along the shortest tape of the solution current, m / day,
τ _i = T _s + ndτ time, days,
n = 1,2,3 ... dτ specified time interval, days,
K ₁ , K ₂ , K ₃ , K ₄ constant coefficients obtained from equation (2) according to the results of laboratory tests of core material taken from the ore body, and when drilling wells maintain the ratio:
l _i / b 1/7 1/8
where b is the distance between the nearest rows of pumping and injection wells, l _{i is the} distance between the nearest wells of each row.

The drawing shows the location of the wells for injection of leaching and pumping productive solutions, a picture of the flow of the solution in ore-containing rock, where 1 injection wells, 2 pumping wells, 3 - solution flow tapes, 4 shortest current tape between the nearest injection and pumping wells, b distance between the nearest rows of pumping and injection wells, l _{i the} distance between the nearest wells in each row.

Example. The invention was used in the development of the Uvanas uranium deposit in Kazakhstan, which is characterized by the following averaged data: average thickness of the ore-containing formation 10 m; the reservoir is located within the boundaries of the upper and lower water confines, which are represented by thick clay deposits; volumetric weight of the ore mass is 1660 kg / cm ³ ; effective porosity 30%
The ore body was opened by alternating rows of injection and pumping wells, as shown in figure 1. The computer-generated picture of the flow of the solution in the ore body is also shown here. On the core material taken from the ore body under laboratory conditions, the coefficients K ₁ , K ₂ , K ₃ , K _{4 were} determined, which are characterized by the dynamics of the interaction of the reagent with the ore-containing rock. The coefficients were calculated according to equation (2) for various values of l, C, V _f . The injection process was started with the maximum concentration of the reagent in the leach solution, which was kept constant during the initial period, and then the concentration of the reagent was continuously reduced in accordance with equation (1). Sulfuric acid with additives of oxidizing agents and complexing agents was used as a reagent. The initial concentration of the reagent in the leach solution was 20 g / L.

During the development of the Uvanas field, several variants of well networks were tested. The optimal ratio was
l _i / b 1/7
The above dependences were obtained by summarizing data on various deposits of the hydrogenic type, therefore, this method can be used for mining by underground leaching of a wide variety of minerals and, above all, metals (Cu, U, Re, Sc, Mo, V, etc.). The accumulated wide experience in the application of this method shows that it allows you to maintain a stable economically most appropriate concentration of useful components in a productive solution with a significant reduction in the time of field development, reagent consumption and a corresponding reduction in costs. For example, during the development of the Uvanas field, the mining time of one of the blocks drilled by the proposed method was reduced by 44.4%, while the specific acid consumption decreased by 13% and the cost of mining a unit area decreased by 46.6%. It should be noted that the use of this a method that guarantees a significant reduction in reagent consumption and solution volume, minimizes the negative impact on the environment.

Claims (2)

1. A method of underground leaching of minerals, including opening the ore body in alternating linear rows of injection and pumping wells, pumping the leach solution into the injection wells with adjusting its parameters, and pumping the product solution through the pumping wells, characterized in that the process begins with the maximum concentration of the reagent in the leaching a solution which is maintained constant during the initial period and then the concentration of the reagent is continuously reduced in accordance with awn

where T _{with the} time of the initial period, days;
C maximum concentration of reagent, g / l;

l the length of the shortest leaching solution current tape between the nearest injection and pumping wells m;
V _f the filtration rate along the shortest tape of the solution current, m / t day;
τ _i = T _s + ndτ time, days;
n = 1,2,3 ... dτ specified time interval, days;
K ₁ , K ₂ , K ₃ , K ₄ constant coefficients obtained from equations (2) according to the results of laboratory studies of core material taken from the ore body. 2. The method according to claim 1, characterized in that when drilling wells maintain the ratio
l _i / b 1/7 1/8,
where b is the distance between the nearest rows of pumping and injection wells;
l _{i the} distance between the nearest wells in each row.