SU1705565A1 - Method of stowing goafs in mining steep deposits of valuable minerals under conditions of permafrost - Google Patents

Abstract

The invention relates to the development of fields with the laying of ice. The goal is to increase the safety of mining operations in the presence of rock salt in the host rocks. The upper part of the field is mined by a quarry and an ice massif is formed in the developed space in a volume determined by the calculation formula. The remaining reserves are developed by the underground method with the laying of the developed space with ice under the action of its own weight from the spent quarry. On the ice massif place a layer of bulk filling material. Then, the ice massif and the layer of loose material move as the underground mining is lowered by the mass of the additional ice massif. The latter is frozen on top of the bulk material. 3 il. ate with

Description

The invention relates to mining and can be used in the development of steeply dipping ore bodies. permafrost, including rock salt formations, such as kimberlite pipes;

The purpose of the invention is to improve the safety of mining operations in the presence of rock salt layers in the host rocks.

1. Figures 2 and 3 show the deposits by the stages of excavation of the mineral and laying of the developed space, vertical sections.

The method is carried out as follows.

In the surrounding rock body 1 rocks 2 there are several layers of rock salt 3. The upper part of the ore body is mined by quarry 4. By the time the open-pit mining is completed, the deposit is completed by underground mining. For one or several winter seasons at the bottom of the spent pit 4, they freeze the ice massif 5, the volume of which is determined; divided by the formula

V1

, nt

(one)

S-Hk + t (+ 0.5JrSp),

where S is the ore body area, m2;

Hk - the minimum thickness of the ice layer is necessary, not destroyed by blasting, m;

VI

ABOUT

ate

Och

ate

t - the time of mining stocks to the level of the zero isotherm, year;

ht - the amount of process heat entering the mine workings for 1 year, “cal;

g is the specific heat of ice melting,

Kcal / m3;

Sp is the contact area of rock salt beds with ice, m;

g} is the rate of salt leaching upon contact with ice, m / year.

By the end of the first winter period after mining, the rifling works are completed and the underground cleaning works in the remaining mineral reserves are completed with ice being laid out.

The ice from the spent pit sinks down the depleted space as the cleaning works 6 progresses and fills the depleted space under its own weight.

After freezing the ice massif of the required volume, a layer of waste rocks 7 is poured onto its surface. The volume of which is determined by the formula

VC-S- / 3 (), (2) where ft is the coefficient taking into account that part of the bulk material remains on the berms and does not enter the developed space;

U - roof mark of the upper salt layer, m;

 - mark the soil of the lower layer of salt, m;

S - ore body area, m2.

An additional layer of ice 8 is frozen on the surface of the bedrock layer.

The ice massif and the layer of loose material from waste rock as the underground mining is lowered are moved by the mass of the ice massif 8.

.

Claims (1)

The invention method of laying the developed space in the development of steeply dipping deposits of valuable minerals in permafrost conditions, including the mining of the upper part of the month: torodalization, formation of an ice massif in a spent quarry, underground mining of the remaining mineral reserves with the laying of the developed space with ice under the influence of its own the weight of the spent quarry, characterized in that, in order to increase the safety of mining operations In the surrounding rocks of the rock salt layer, the formation of the ice massif in the spent quarry is carried out in the volume determined by the formula 20 25 35 40 30 / t / ht V I-S-Hk + t (- + 0.5J7 Sp), where S is the ore body area, m2; Hk - the minimum thickness of the ice layer is necessary, not destroyed by blasting, m; t - the time of mining stocks to the level of the zero isotherm, year; ht - the amount of process heat entering the mine workings for 1 year. Kcal; g is the specific heat of ice melting, Kcal / m3; Sp is the contact area of rock salt beds with ice, m2; rj is the rate of salt leaching when in contact with ice, m / year, a layer of bulk filling material is placed on the ice massif and the ice massif and bulk material layer are moved to the subsurface mining number with the weight of the additional ice mass that is frozen above the bulk material.