DD220980A1 - MEANS FOR PRODUCING SEALING ELEMENTS - Google Patents

Abstract

The invention relates to a means for producing sealing elements in areas containing ferrous groundwater. The extraction of lignite in open pit mining usually requires a drainage of the subsoil. To ensure geotechnical safety, groundwater rise must be prevented or minimized for a while. It was necessary to find a means which triggers a sealing effect by utilizing chemical reaction processes when digested in the groundwater of dissolved iron. It was found that Kraftwerksasche alone or in combination with clay, cement or calcareous Schlaemmen, applied in the form of fins perpendicular or parallel to the water flow direction or even applied surface, produces the desired buffer effect. Areas of application are standing and tilting buoys, sealing walls or sealing carpets when operating opencast mines or in hydraulic engineering measures.

Description

Means for producing sealing elements Field of application of the invention

The invention relates to a means for producing sealing elements in areas containing ferrous groundwater. Extraction of lignite in open pit mining usually requires drainage of the subsoil. This often has to be operated for a while after tilting the roughing masses for a while in order to prevent the green water rising in the dump area to ensure geotechnical safety. In the underground are often iron-containing minerals contained, especially in the vicinity of Braurikohlenflözen they occur in the form of iron sulfides. Weathering and dissolution processes cause iron-containing and acidic groundwaters

Characteristic of the prior art

In the execution of construction work in the underground, it is often necessary to lower existing groundwater or prevent the groundwater inflow hu. The latter happens in particular through the use of sealing elements and is mainly important in long-term construction measures *

In water and earthworking sealing elements are known, which are used to prevent or limit the seepage of construction

• In order to prevent or limit the infiltration of open water surfaces into the subsurface, they are preferably produced from foils, clay, loam, concrete, bitumen, chemicals or combinations thereof.

The "Neue Bergbautechnik ¹¹ (3/1973) describes a method of subsurface sealing based on the oxidation of iron (II) and the precipitation of iron (III) oxide hydrate using oxygen as an oxidizing agent The addition of chlorine is intended to prevent the onset of obstruction.The chemicals are brought into the underground by means of infiltration wells.This procedure has the following disadvantages:

The upcoming waters usually have low pH, but since the pH is the dominant factor in the oxidation, only insignificant amounts of iron (II) are oxidized purely chemically, with which no sealing effect can be achieved. Furthermore, there was a killing of the iron-oxidizing microorganisms of the type Thiobacillus by the chlorine addition. The entire system has only a short life by the Kolmation the well near the room, with a complete seal seems impossible because a uniform deposition of iron hydroxides is not controllable. To eliminate remaining hydraulic contact zones, the distance of the infiltration wells must be kept very low according to the given geohydraulischen conditions. Since, in addition to the infiltration wells, pumping wells still have to be installed, there is a high outlay ¹ on material, drilling capacity, energy and manpower. Also, the period of time from the beginning of the infiltration of oxidants to achieve a sealing effect in the underground is very long.

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Object of the invention

The aim of the invention is to achieve a targeted, localized sealing dee substrate against existing and inflowing groundwater in open pit mining by compaction phenomena and cementation effects.

reading the invention

The invention has for its object to find a means, preferably a waste product, and to use, which triggers a sealing effect by utilizing chemical reaction processes in the precipitation in the groundwater dissolved iron.

According to the invention, this is achieved by accumulating power plant ash alone or in combination with clay, cement or lime-containing sludges in the form of lamellae, which are arranged perpendicular or parallel to the water flow direction and are also applied flatly, whereby standing and tilting slopes are provided , Sealing walls or sealing carpets when operating opencast mines or during hydraulic engineering measures during the operating period.

Implementation Example ^

With reference to an embodiment, the invention will be described in detail.

If an open-pit mine is reopened, power plant ash, alone or in conjunction with clay, cement or lime-containing sludge, is applied to the ledge in the form of a lamella prior to the start of the tilting process. As the open pit development progresses, the headland is also provided with an ash lamella, thus sealing the entire tipping system against edge fill. Power plant ashes alone or in the above-mentioned compounds can also be applied to tipper slopes in opencast mines #

also for the sealing of slopes of open pit holes, where a flow of water from the residual hole in the mountains or an influx from the mountains must be prevented in the residual hole. In both cases, anti-corruption measures are required in the club. , -

Furthermore Kraftwerkoasche should be used as a buffer substance as a sealing material in milled slots of sealing walls.

Another application as a sealing carpet is in the case of river entrenchments or the construction of earthquakes in mine water treatment plants] !, in order to minimize infiltration of the subsoil.

The assessment of the thickness of the ash slate is carried out in accordance with 'practical uranium enrichment tests of groundwater containing iron, taking into account the buffer capacity of power plant ash. The most important design parameter is the iron-proton ratio.

Advantages of using the solution according to the invention result from a reduced effort in Kippcnentwässerungsarbeiten, shorter service life of Randriegeln and extensive localization of groundwater contamination by reaction products on the tilted areas that arise in the weathering of bis-sulfides.

In cases where a cancellation of the sealing effect is required after the setting of the mining activity, the ash layer is destructible by blasting. This creates the conditions for the restoration of an additional groundwater regime.

Claims (1)

I saw English spoken Means for the production of sealing elements in areas containing ferrous groundwater to ensure the geotechnical safety in the operation of opencast mines, which triggers a Äbdichtungseffekt using chemical reaction processes in the precipitation in groundwater iron, characterized in that Kraftwerksasche alone, in combination with clay, cement and calcareous sludges in the form of lamellae, which are applied perpendicular or parallel to the direction of water flow, as well as applied flat, with standing and Kippenböschungen, Dichtungswänöe or seal ung-setppiche when operating opencast mines or in hydraulic engineering applications are applications.