RU2270921C1 - Backfill mix - Google Patents

Abstract

FIELD: mining industry, particularly to develop mineral deposit along with backfilling of worked-out areas.

SUBSTANCE: backfill mix comprises cement, grinded granulated blastfurnace slag, filler and water. The backfill mix additionally has shredded straw. Grinded diabase is used as the filler. All above components are taken in the following amounts (% by weight): cement - 2.9-5.07, grinded granulated blastfurnace slag - 15.21-16.91, grinded diabase - 52.24-53.22, shredded straw - 0.02-0.076, water - remainder.

EFFECT: increased strength and crack-resistance.

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Description

The invention relates to the mining industry and can be used in the development of mineral deposits with the laying of the developed space.

Known filling mixture, including cement, ground granulated blast furnace slag, aggregate and water, taken in the following ratio of components, wt.%:

Cement 2 Ground granulated blast furnace slag 18,4 Aggregate 61.38 Water Rest

(see L.K. Vakhrushev, E.M. Denisov, K.Yu. Repp. Use of dump blast-furnace slag for preparation of knitting filling mixture. Mining Journal, 1979, No. 1, p. 39).

The disadvantages of the known mixture are low ductility due to the fact that the content of the fine fraction of the class - 0.14 mm less than 600 l / m ³ leads to delamination of the mixture, as well as low strength (3.0 MPa in 90 days) of the constructed array due to the use of aggregate with a tensile strength below the normative strength of the bookmark.

The closest analogue to the claimed object is a filling mixture, including cement, ground granulated blast furnace slag, aggregate - sand and water, taken in the following ratio of components, wt.%:

Cement 1.4-2 Ground granulated blast furnace slag 18.8-19.9 Sand 62.8-63 Water Rest

(see A.L. Trebukov. The use of hardening bookmarks in underground ore mining. - M .: Nedra, 1981, p.31).

The disadvantages of this mixture are low strength (4.5 MPa in 180 days) and low crack resistance during the construction of the filling array. This is due to the increased content of the binder and water in the mixture, which causes uneven volumetric deformations during the hardening of the mixture, leading to the appearance of shrinkage cracks.

The technical problem solved by the invention is to increase the strength and crack resistance of the filling mixture.

The problem is solved in that the known filling mixture, including cement, ground granulated blast furnace slag, aggregate and water, according to the invention additionally contains crushed straw, and as a filler - ground diabase in the following ratio of components, wt.%:

Cement 2.9-5.07 Ground granulated blast furnace slag 15.21-16.91 Ground Diabase 52.24-53.22 Shredded straw 0.02-0.076 Water Rest

It is known in the chamber system for the development of mineral deposits to use straw stalks as a damping layer, which provides elastic compliance to the walls of the ice pillar relative to the wall of the chamber to be laid (see ed. St. USSR No. 815320, E 21 F 15/00).

In the inventive filling mixture, the crushed straw exhibits a new technical property, which is to ensure that the reinforced fiber of the constructed artificial massif is reinforced with straw fibers, which makes it possible to evenly distribute volumetric deformations in the hardening massif and thereby prevent the appearance of shrinkage cracks. The presence of chopped straw in the backfill array also helps to accelerate the drainage of excess water from it.

In addition, the fibers of crushed straw, having high hydroscopicity, quickly absorb water (within 0.3-0.5 minutes), thereby ensuring a sufficiently high mobility and plasticity of the filling mixture, which eliminates its delamination both during transportation and during hardening filling array.

Thus, crushed straw, having a set of properties, helps to increase the crack resistance of the constructed artificial massif, while ensuring its high strength.

Known use in hydraulic tab crushed diabase as a filler (see Bookmarking work in the mines: a Handbook / Under the editorship of DM Bronnikov, MN Tsygalov - M .: Nedra, 1989, p.259).

In the inventive filling mixture, ground diabase is also used as a filler.

However, along with the known technical property in the inventive mixture, ground diabase exhibits a new technical property, which consists in regulating the homogeneity of the filling mixture by creating a carrier finely dispersed medium of slurry particles (fractions less than 0.14 mm) of diabase, which ensures uniform distribution of cement and slag particles in volume due to their suspended state. This increases the ductility of the filling mixture, increases its mobility, which eliminates the stratification of the filling mixture during transportation, as well as during hardening of the array. All this leads to increased strength and crack resistance of the filling mass.

Based on the foregoing, we can conclude that the inventive filling mixture does not explicitly follow from the prior art, and therefore meets the patentability condition "inventive step".

The inventive filling mixture is prepared as follows. First, granular blast furnace slag and diabase are ground in a ball mill to a particle size of 40% class - 0.074 mm, then M400 brand cement, water and ground straw having a fiber length of 30-40 mm are added. All of the above components of the filling mixture are taken in the claimed amount. Then the resulting mixture is stirred until a homogeneous consistency, after which the filling mixture is ready for use.

To substantiate the advantages of the inventive filling mixture in comparison with the prototype, as well as to justify the quantitative content of the components in the inventive mixture in laboratory conditions, six compositions of the filling mixture were prepared and tested: compositions No. 1-3 were taken with the claimed content of the components; composition No. 4 - with the content of components that go beyond the minimum value; composition No. 5 - with a content of components that goes beyond the maximum value; composition No. 6 was taken on the prototype. The compositions of the filling mixtures are given in table. one.

Table 1 Compositions The content of the components of the mixture, wt.% Cement Ground granulated blast furnace slag Ground Diabase Sand Shredded straw Water Number 2 3.9 15.9 52.9 - 0,049 27,251 Number 3 5.07 16.91 53.22 - 0,076 24,724 Number 4 1.9 14.34 51.22 - 0.014 32,526 Number 5 6.1 14.34 51.22 - 0.1 28.24 No. 6 prototype 2 18.36 - 61.22 - 18,42

For testing, samples 10 × 10 × 10 cm in size were prepared. After hardening, the samples were kept under a layer of wet sawdust. Tests of samples No. 1-6 for mechanical strength were carried out by a hydraulic press after 28, 90 and 180 days, in accordance with GOST 10180-85. The test results are shown in table.2.

table 2 Compositions Characteristics of the filling mixture The compressive strength of samples (MPa) in age, days Draft cone StroyTSNIL, cm The tensile strength of the samples (MPa) in age, days 28 90 180 180 No. 1 1,61 3.01 4.95 11.5 0.475 Number 2 2,3 3.43 5.12 11.5 0.481 Number 3 2.2 3.25 5.1 11.3 0.478 Number 4 1,67 2.69 4.33 11.5 0.434 Number 5 1,53 2.88 4.23 10.5 0.412 No. 6 prototype 1,67 2.93 4,55 10 0.432

The test results shown in table 2 showed that the inventive filling mixture (compositions No. 1-3) compared with the filling mixture (composition No. 6), taken as a prototype, has:

- increase of 8.8-12.5% compressive strength at the age of 180 days;

- increase by 9.9-11.3% of tensile strength, which confirms the high crack resistance of the filling mass;

- increase by 13-15% of the mobility of the mixture.

The use of filling mixtures with a content of components that go beyond the declared limits is impractical due to the insufficient strength of the filling array (composition No. 4, 5), as well as its low crack resistance (composition No. 5).

Claims (1)

The filling mixture containing cement, ground granulated blast furnace slag, aggregate and water, characterized in that it additionally contains crushed straw, and as a filler - ground diabase with the following content of components, wt.%: Cement 2.9-5.07 Ground granulated blast furnace slag 15.21-16.91 Ground Diabase 52.24-53.22 Shredded straw 0.02-0.076 Water Rest