RU2299328C2 - Method for extracting gravel deposits under reaches of rivers, located in permafrost zones - Google Patents

Abstract

FIELD: mining industry, in particular, extraction of gravel deposits by open method in permafrost zones under river beds, having alternation of crossings freezing in winter and non-freezing reaches.

SUBSTANCE: method includes drying a section of gravel deposits by draining water with pump plant, removal of ice and extraction of resources. Draining of water and extraction of resources is performed in winter period after freezing of crossings.

EFFECT: increased quantity of extracted resources.

Description

The invention relates to mining, in particular to the development of alluvial deposits in an open way in areas of permafrost.

Currently, in areas with harsh climates, a significant number of alluvial deposits are being developed by open pit mining. The most complex deposits remain undeveloped, for example, if they stretch for several kilometers, and the main reserves are located in loose sediments under the river channel. On small and medium rivers, rifts alternate with reaches. The rifts are shallow, therefore, in winter, after freezing in these areas, seizure is possible. This method is used, for example, in the extraction of diamonds in Yakutia.

On the stretches, due to their great depth, mining of reserves is technically possible only in the summer with floating mining machines, such as dredges or dredgers. However, due to the increased rockiness of the deposits (boulders larger than 600 mm), the use of a dredger is not possible. If you use the dragee method, then due to the increased size of the boulders, a powerful dredge will be required (with a scoop capacity of at least 250 liters and a mass of about 2000 tons), which is unacceptable for small deposits due to large capital investments. In addition, existing environmental legislation prohibits the operation of drags in running water.

The invention is directed to creating a method for developing placers in the stretch areas of a deposit that cannot be worked out by known methods.

There is a method of developing areas of alluvial deposits, in which a dredger (dredge) is used to extract reserves from under the water. At the same time, the field is not drained, and reserves are excavated in the warm period (1).

The disadvantage of this method is the high loss of reserves in the bowels, the inability to develop coarse-grained rocks and an unacceptable level of environmental pollution of the watercourse when working in an open riverbed. Losses of reserves are caused by inevitable inter-step pillars and the movement of part of the loose reserves by the river beyond the zone of the developing body. The extraction of reserves from under the water eliminates the possibility of visual and instrumental control of the completeness of the formation. When reserves are developed in the flow channel, an inadmissible quantity of suspended pollutants from the working area of the developing body into the watercourse is unavoidable for environmental standards. In addition, work in a flowing reservoir involves unplanned downtime during periods of passage of flood water.

There is also known a method of developing alluvial deposits under water, which is adopted as a prototype, as the closest to the claimed technical solution (2). The method includes drainage of the placer sites and extraction of reserves, which is carried out in the summer.

In the known method, drainage of the placer sections is carried out by diverting a river bed (surface runoff) into a bypass (channel runoff) channel and removing ground (underground) runoff through a network of drainage openings.

The disadvantage of this method is that its use requires the presence of free areas in the valley of the field suitable for relief for the construction of a bypass (channel) channel, and during its construction, if the required area is available, additional surface areas are violated. The capital expenditures for the construction of such a channel are quite large. The main disadvantage is that in this way it is impossible to completely drain the bowl of the reach.

The problem to which the present invention is directed is to provide the possibility of mining the placer areas of the placer and thereby increase the efficiency of the development of a raw material base located in severe climatic conditions.

The technical result that can be obtained from the use of the invention is to increase the number of recoverable reserves by involving placers in the development of stretch areas.

The specified technical result is achieved due to the fact that in the method of developing alluvial deposits under river reaches located in permafrost distribution areas, including draining the placer site and excavating reserves, according to the invention, the stretch site is drained in the winter after the freezing of the rocks by pumping water, placer located on the ice surface of the placer, then ice is cleaned and reserves are removed.

The specified set includes features, each of which is necessary, and all together are sufficient to achieve the technical result.

When draining the stretch by pumping out water in the winter, when the active loose layer first freezes, which excludes the entry of groundwater along the coastline, and then loose deposits on the rifts freeze and the movement of groundwater under the river bed stops, the natural phenomenon of complete isolation of water in the bowl is used reach from any of its revenues from the outside.

Comparative analysis shows that the proposed method differs from the prototype. This allows us to conclude that the invention meets the criterion of "Novelty."

To prove the compliance of the invention with the criterion of "Inventive step", an additional search and comparison with other technical solutions known from sources was carried out.

As a result of the search for ways to develop stretch areas of placer deposits in the areas of permafrost distribution using drainage by pumping water with a pumping unit with extraction of reserves in winter, it was not found.

The inventive method of developing stretches of placer deposits in permafrost areas meets the criterion of "Inventive step", because the combination of its distinctive features makes it possible to work out the stretches of placer deposits in permafrost areas with minimal mineral losses in the bowels and with acceptable environmental damage to the environment, which cannot be drained by surface runoff and drainage, which is not obvious from a known level technicians.

To prove compliance of the invention with the criterion of "Industrial application", it should be indicated that its use in the experimental procedure was carried out in 2005 at the enterprise of OAO Nizhne-Lenskoye (Republic of Sakha-Yakutia).

The method is as follows. After the establishment of ice and freezing of the rifts, when the surface and ground runoff of water stops, a pump station is installed on the ice of the stretch site. Having determined the volume of water in the reach and given the permissible duration of the process of pumping water, select the required pump capacity.

The place to install the pumping station is chosen in the deepest place as close as possible to the lower boundary of the site. The pumped-out water is supplied by the shortest distance along the pipe to the coastal edge. The pipe is laid on a leveled track or a dam constructed of snow with a reverse slope to ensure gravity-free emptying of the water conduit in case of pump stops. Water is discharged from the pipe through the crest of a specially designed snow enclosing embankment into a trench constructed along the coastal edge in the snow, which passed down the river. When lowering the ice on the stretch during the pumping of water, such a trench does not change the bottom mark, which ensures unhindered leaving of the pumped water.

Upon completion of the pumping water, ice is removed from the drained area and reserves are excavated by a bulldozer or excavator method. The extracted reserves are stored at the site of the processing plant for subsequent processing in the summer.

The use of the invention in comparison with the known technical solutions will allow:

1. To carry out the extraction of reserves from the stretches of placer deposits located under the water of rivers in areas of permafrost with minimal loss of minerals in the bowels.

2. To minimize environmental damage.

3. To increase the number of developed deposits.

Information sources

1. Shorokhov S.M. Alluvial deposits development and design basics. M .: Gosgortekhizdat, 1963. P. 27.

2. Shorokhov S.M. Alluvial deposits development and design basics. M .: Gosgortekhizdat, 1963. p. 59 (prototype).

Claims (1)

A method of developing alluvial deposits under river reaches located in permafrost areas, including draining of the placer and extraction of reserves, characterized in that the draining of the stretch is carried out in the winter after freezing of the rocks by pumping water placed on the ice surface of the stretch, then carry out ice cleaning and extraction of stocks.