UA25473U - Method for current prediction of methane content - Google Patents

Abstract

A method for current prediction of methane content includes collection of data on concentration of methane and amount of air by data of air-gas control in effluent lava flow or production section.

Description

Description of the invention

The useful model refers to the mining industry and can be used for operational forecasting of 2 methane content of underground mine workings, on the basis of which management of ventilation of mine workings is carried out, design of ventilation of coal mines, selection of means and methods of gas release management, determination of optimal loads on cleaning faces according to the gas factor, as well as solving a number of problems directly related to ensuring safe working conditions.

There is a well-known method of forecasting the methane content of products of mining areas for operating mines based on the actual 70 methane content of the product-an analogue of this mine layer (statistical method), which consists in collecting data on the mining-geological, mining-technical conditions of mining operations; about the concentration of methane and the amount of air in the outflowing stream of lava or the mining area, and based on the obtained data, the average forecast methane content of the production is calculated based on the average methane content of the analogue product for the entire period of extraction of the lava pit field. 19 According to the statistical method, the predicted methane content of the mine workings is determined by the actual methane content of the workings-an analogue of the given mine layer (Ir, m/min): 04 ov m/min.

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The predicted methane yield for the designed production is established by correcting the actual methane yield of the analogue bench (If, m/min.) taking into account the regularities when changing the parameters: length of the bench (- ocher m), load on the cleaning face (Ар, t/d .), systems of development (ksr.) and natural methane bearing capacity with depth (kgr.) | Guide to the design of ventilation of coal mines. - Kyiv: Osnova, 1994. - P.3111.

Disadvantages of the known method - only the average value of the methane content of the treated product is predicted for the entire period of mining of the excavation field, which does not allow predicting the level of methane release at a specific moment in time due to the fact that the dynamic nature of methane release, caused by the heterogeneity of the massif and the unevenness of the flow of geomechanical processes, is not taken into account. The method cannot be used when opening new layers, changing the method of managing the roof, when sub- or chipping the layer. co

The technical task of the useful model is to improve the method of current forecasting of methane production, in which the application of the method of exponential smoothing with a previously established empirical coefficient - for specific production conditions and the new principle of selecting the forecast values of methane production at the initial moment of time allows for the current forecast of methane production in space and time, taking into account of the integral influence of all development factors, the mean absolute percentage error (MARE) of which is 1090, which is 2 times lower than the generally accepted in the coal industry. Ge

The task is solved as follows: in the method of the current forecast of methane production, which includes the collection of data on the concentration of methane and the amount of air according to the data of air and gas control in the outflowing stream of lava or mining area according to a useful model, the calculation of the actual methane release from the lava or mining area is carried out in a time of at least 6 days after the period of primary subsidence of the roof massif, on the basis of the obtained data, a dynamic series of the actual average daily methane emission is constructed for a specific bench, and the predicted methane content of the bench or extraction site is determined by the method of exponential smoothing according to the formula: /min. where Ii is the forecast value of methane content at this moment in time (the last calculated forecast 7 value obtained at the previous time step is taken), the input data for the current operational forecasting of methane content is the arithmetic average of the average daily methane content values for the last 6 days of operation of the station, at mZ /min.; i» IV- f active value of the methane content for the previous day, m/min.; - and 20 t. the empirical smoothing coefficient, which reflects the integral influence of almost all factors that are difficult to take into account: physical and mechanical properties of rocks, lithologic-powerful structure of sub- and fractured massifs, c» unevenness of roof subsidence and the degree of disturbance, and the coefficient a is chosen optimal in each specific case based on the minimization of the forecast error, which allows for the current forecast of methane release in space and time taking into account the integral influence of all development factors, 25 the average absolute percentage error (MARE) of which is 1095, below the generally accepted in the coal industry.

In Fig. an illustration of the implementation of the proposed method is provided, curve 1 is a dynamic series of actual methane release, curve 2 is a forecast methane release calculated by the method of exponential smoothing. because the Method is carried out in this way.

To compile the current forecast of methane content of the mining site, the actual average daily data on the concentration of methane and the amount of air according to the data of air gas control (CAGI), for example, for 3 days of work after the initial planting of the roof massif, are written out. The actual average daily flow rate of methane is calculated, based on these data, a dynamic series of actual gas release for the selected period of operation of the site is constructed. (All calculations are performed according to the Manual) (curve 1 Fig.).

The forecast value of methane emission is calculated by the method of exponential smoothing according to the formula:

In - I. same (r that these 'm'/min. 9 where Iii is the forecast value of the methane rate at the current moment of time (the last calculated forecast value obtained at the previous time step is taken), the input data for the current operational forecast of the methane rate is the arithmetic mean average daily methane rate values for the last 6 days of work, m/min.;

IV - the actual value of the methane content for the previous day, m/min.; 70 95 - empirical smoothing coefficient, which reflects the integral influence of almost all factors that are difficult to take into account: physical and mechanical properties of rocks, lithologic-powerful structure of sub- and crushing massifs, unevenness of roof subsidence and the degree of disturbance, the coefficient a is chosen as optimal in each specific case based on minimizing the forecast error.

When the forecast calculation is performed for the first time, the forecast value of methane yield obtained at the previous 75 time step is found as the average arithmetic value of methane yield for the last six days of work: b

The data must be representative, that is, the values taken must not contain missing or incorrect values.

The actual value of methane content is taken for the last day.

IFTS

We select the smoothing coefficient so empirically using data on the actual daily average values of methane content for a specific period of operation of the site. For the studied mines of Donbas, it was established that a can be equal to 0.5-0.7. During operational forecasting of methane yield, a remains constant for the given mining conditions for the period of operation of the mining site. WITH

All further calculations of the predicted value of methane content I..4 are carried out as follows: I2 (methane content is calculated based on yesterday's actual measurements); Ii (methane content predicted yesterday for today) (curve 2 Fig.).

It should be borne in mind that a random error in the performance of even one calculation can affect the results in the future. This is due to the use in the calculation formula of the parameter I!, which contains the entire background history of the parameter change. Therefore, when a random error is detected, it is necessary to recalculate all calculations performed since the error was detected. "

To control the quality of the forecast, the mean absolute percentage error (MARE) is calculated. This indicator characterizes the accuracy of the forecast. iv) '-1 - marv-1 In or cm half I

The calculation is performed using the Ehsei program, which is part of the Misgozoi OPise package.

An example of using the method. "

The current forecast of methane production by the method of exponential smoothing is given for the conditions of extraction of lava 25 of the Orlov deposit of the Molodogvardiyskaya mine of JSC Krasnodonvugillia. First, the actual methane emission of the site (IF) is calculated. for example, for a month of work (see table), according to the calculated data. ," build a dynamic series of the actual methane release (curves in Fig.) To calculate the predicted methane release (I)) a smoothing factor was adopted: -0.5. Next, a dynamic series of predicted methane emission was constructed (curve 2 in Fig.). As can be seen from the curves in Fig. forecast values generally reflect the dynamics of changes in actual methane release and have sufficient convergence and accuracy.

For the given example, the average absolute percentage error of MARE is 895, which confirms the high accuracy of the forecast (see table).

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Methane release forecast of the mining site in the village of

Date of work Actual methane extraction of the site, Predicted methane extraction of the site |Module of absolute error, e Relative error, 95 pin nin nn nn non ny bo 1 s myu |tys vyv tyu av |v ve 00111vyu0000011vya00110 60 vv 11.12.03 7.70 7.82 0, 22 2.90 t8l203 2100 12.23.03

The accuracy of the MARE forecast is 90 percent

Claims (1)

The formula of the invention is the method of the current prediction of methane production, which includes the collection of data on the concentration of methane and the amount of air according to the data of air and gas control in the outflowing stream of lava or mining site, which differs in that the calculation of the actual methane release from lava or mining site is carried out in a time of at least 6 days after the period of primary subsidence of the roof massif, on the basis of the obtained data, a dynamic series of actual average daily methane emission for a specific lava is constructed and the predicted methane content of the lava or mining site is determined by the method of exponential smoothing according to the formula: - t. : f ) m/min s Name Ba -1) where Ii is the forecast value of the methane rate at the current moment of time (the last calculated forecast value obtained at the previous time step is taken), the input indicator for the current operational forecasting of the methane rate is the arithmetic mean of the average daily the values of the methane content for the last 6 days of the operation of the station, m/min.; -о с И: - the actual value of methane content for the previous day, m³/min.; Из» А is an empirical smoothing coefficient that reflects the integral influence of almost all factors that are difficult to take into account: physical and mechanical properties of rocks, lithologic-powerful structure of sub- and overcracked massifs, unevenness of roof subsidence and the degree of disturbance, and the coefficient A is chosen as optimal in 45 on a case-by-case basis based on the minimization of forecast error. 1 ChK" - i syu 60 b5