Transcript Diapositiva 1

12th U.S. / North American Mine Ventilation Symposium
Reno, Nevada June 2008
Ventilation Planning at the Minerales Monclova’s Mines
J. Ruben Ponce Aguirre
Minerales Monclova, S.A. de C.V., Mexico
COAHUILA STATE LOCATION
Cd. Acuña
N
Piedras Negras
2
10
1
5
3
6
4
9
7
8
Torreón
Saltillo
Cd. Acuña
Coal sub-basins in Coahuila
Piedras Negras
2
10
1
5
3
6
4
9
1.1.-Sabinas
Sabinas
2.Las
2.- LasEsperanzas
Esperanzas
3.Saltillito
3.- Saltillito
4.4.-San
SanPatricio
Patricio
5.San
Salvador
5.- San Salvador
6.6.-Adjuntas
Adjuntas
7.Monclova
7.- Monclova
8.8.-Castaños
Castaños
9.Cuatro
9.- CuatroCiénegas
Ciénegas
10.-Fuentes-Río
10.-Fuentes-RíoEscondido
Escondido
7
8
Mine 6 operates in the Sabinas Basin
Torreón
Saltillo
The current Minerales Monclova’s
mines operate in the Sabinas and
Saltillito Coal Basins.
COMPANY BACKGROUND
In the last 17 years the Minerales Monclova’s ( MIMOSA )
underground Mines
have developed 534,126 meters in
developments and a total longwall panel retreat of 63,369
meters for a ROM coal production of 65,812,000 tons.
To do this 15 Alpine AM-50 and 3 IBS SM-130 roadheaders are
currently in use.
In the longwalls, JOY 4LS shearer machines and DOWTY and
DBT shields with 2 or 4 legs are used and the last year a brand
new plow system for low coal seams mining started working
also.
The longwall mining is performed using the dual entry
system.
CURRENT VENTILATION SITUATION
The tipical layout for the MIMOSA’S mines is the following:
The current operation depth goes from 180 to 300 meters
due to the different location of the mines in the coal basin.
The methane concentration in the coal seam is in a range
from 8 to 18 m3/ton.
The access to each mine is provided with to parallel slopes
supported with steel arches, one slope is used for materials
supply and people and the other is used for the main belt
installation.
The mains have 4 entries supported with steel arches and
the longwall panels have an average length of 2 km and 250
meters wide.
These dimensions were increased in the last years from a
length of 1 km. to the current 2 km. and the width was 200
meters instead of the actual 250 meters.
To achieve the ventilation demands for all these changes
the size of the airways have been upgraded from 8 m2
supported with steel beams and wood timbers to the actual
15m2 supported with steel arches.
The 2 entry system is used for the longwall system and a
wrapped around bleeder system is used for the ventilation.
Mine Layout
0
500
1000
1500 meters
LONGWALL VENTILATION
In the longwall ventilation system, the gob area is isolated
with concrete seals built in each crosscut left behind the
longwall.
A 1 m2 opening with a steel door is used in each seal in order
to bleed methane from the gob to the ventilation system from
the inmediate seal behind the advance.
This opening is closed when the longwall advance gets far
from the crosscut where the seal is located.
LONGWALL VENTILATION
Concrete seals
Next Longwall Panel
Belt
Electric controls
Stage loader
Face conveyor
Monorail
Stoppings
Intake
Return
Gob
DEVELOPMENTS VENTILATION
In the developments a blowing ventilation system is in use.
The ventilation for the development faces is provided with
bisected auxiliary fans SPENDRUP 112-80-1760 with 110 kw
(150 horsepower.)
The air is supplied to the faces using flexible ducting with
1.07 meters diameter ( 42” ).
The developments ventilation system was improved in the
last 2 years, the old fans with 55 kw ( 75 h.p. ) and 0.762 mm
diameter ducting ( 30” ) were replaced with the current bigger
fans and ducting.
DEVELOPMENTS VENTILATION
“Alpine Am-50”
roadheaders
Auxilliary fans
Belt
Intake
Return
METHANE DRAINAGE
In 1991 MIMOSA was bought from the government by
GRUPO ACERERO DEL NORTE and it started working like a
private company.
A methane drainage program with horizontal directional
drilling started in 1992 under a contract with REI Drilling Inc.
from the United States of America.
Under this program approximately 30,000 meters were
drilled.
MIMOSA continued this drilling project until 1999 and after
that, the methane drainage drilling has been done with
MIMOSA’S own people.
Since 1992 trough December 2007 a total of 99,431 meters
have been drilled, , this is an average of 6,600 m/year.
METHANE DRAINAGE BACKGROUND
160
16,000
CH4 degas m3/year ( millions )
120
12,000
80
8,000
40
4,000
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
0
1990
0
Degas drilling mts/year
CH4 vent. m3/year ( millions )
3
methane generation m /year ( millions )
Degas drilling meters/year
600,000
800
450,000
600
300,000
400
150,000
200
0
0
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
309,658 454,810 424,829 386,986 266,026 299,290 356,659 328,147 284,256 396,317
CH4 degas m3/day 25,402 27,302 15,466 38,362 22,982 19,008 38,362 55,901 73,613 38,800
689
739
741
765
669
690
739
741
763
738
Total air m3/s
CH4 vent m3/day
Ventilation m3/sec
CH4 m3/day
The total methane liberation in the ventilation and methane drainage
systems of the underground mines is an average of 400,000 m3 of
methane per day.
MAIN FACTORS FOR THE MIMOSA’S MINES VENTILATION PLAN
Advance and
production
requirements
Methane
concentration in the
coal seam
Main fan
performance curves
Friction factors for
entries
Ventilation
System
Planning
Methane generation
forecast
Development and
longwall equipments
required to work
Volume of air
leaks
Maximum methane
concentrations
allowed by law
Air velocities
allowed
VENTILATION PLANNING PROCESS
The ventilation projections for all the mines are reviewed using
the VNETPC 2003 software, this software has been in use in
MIMOSA since 1989 for the ventilation planning of all our mines
and also for analyzing any major change in the ventilation
systems.
With this software in the last 18 years the correlation between the
predicted results and the real numbers has been from 90 to 95%
and sometimes higher.
The average friction factors for the MIMOSA’s entries have been
obtained from ventilation surveys performed in all the mines using
the gauge and tubing method.
The information of the main fans supplied to the fan data bank of
the software is obtained of the manufacturer’s fan curves and then
an air density correction is applied, after that several situations of
the mining plan are simulated and analyzed.
Table1. Main Friction factors used for Airways
Airway type
Friction factorKg/m
Belt entry15 m
Materials15 m
Return15 m
2
0.0228
2
0.0106
2
0.0141
2
Belt & materials in paralell 15m
2
2 Returns in paralell 15 m
0.0037
0.0035
3
VENTILATION PLAN REVIEW
Several simulations are performed to review the whole project of
the mines but for this paper only will be showed a long term
ventilation analysis for Mine 6.
Mine 6 currently has an air volume of 140 m3/s with 2.6 Kpa fan
pressure, 2 development sections and 1 longwall.
The analysis to accommodate 3 road header development
sections and 2 long walls will be described.
MIMOSA MINE VI Long Term Ventilation Layout
Longwall 2
Developments
section
New vertical shaft projected
Developments
section
Longwall 1
C. 4 SUR No 3
C. 4 SUR No 2
C. 4 SUR No 1
C.
C.
4 SUR
C.
No
4 SUR
No
3
4 SUR
2
No
1
BELTS
C.
3
2
4 SUR
No
C.
4 SUR
No
1
RETURN
No
C.
4 SUR
INTAKE
ASSUMPTIONS FOR THE VENTILATION SIMULATION
•Friction factors for entries are according to Table 1.
•Entry cross section is 13 m2. (The original size is 15 m2, but
the reduction was considered necessary due to possible floor
heaving).
•Entries perimeter is 13.5 m.
•Cross section for overcasts 13 m2.
•The fan data supplied to the software was the SPENDRUP
335-184-880.
•Shaft diameter 5 meters.
•2 Longwalls and 3 developments sections with 6 roadheaders
have to be ventilated.
Long term ventilation simulation
VENTILATION SIMULATION RESULTS
•With the proposed arrangement, the fan operating point
predicted is 300.75 m3/s with a pressure of 2.63 Kpa, in the
blade setting number 3 for the main fan SPENDRUP
335-184-880.
The air volume predicted for the different sections of
the mine is:
•Developments section 1
– 43.48 m3/s
•Developments section 2
– 63.48 m3/s
•Developments section 3
– 42.19 m3/s
•Longwall 1 total return
– 79.79 m3/s
•Longwall 2 total return
– 85.02 m3/s
ACTUAL MINE RESISTANCE VS. PROJECTION
5.0
4.0
JOY M-9650
SPENDRUP
335-184-880
Main fan
Kilopascals
Main fan
3.0
2.0
Current Mine
Resistance
Projected Mine
Resistance
1.0
0.0
0
100
200
300
400
Q air m3/s
500
600
700
CONCLUSIONS
•The ventilation project designed for Mimosa's Mine 6 will allow the mine to
work with 3 development sections instead of the actual 2 and with 2 long
walls 2 km long instead of the actual 1 longwall 1 km. long.
•The projection indicates that the total air volume in the mine will be twice
than the current one ( 300 m3/s vs. 140 m3/s ) with the same fan pressure.
•To accomplish this goal, the old shaft has to be used like auxiliary intake to
low the resistance of the mine.
•The current primary fan has to be replaced. ( The new one has been
ordered )
•A new vertical shaft for exhausting the ventilation of the mine has to be
drilled ( this is already in process )
•The resistance of the mine to the ventilation after all this changes will be 5
times lower than the current.
•A similar ventilation and mine planning project has been done for the other
coal underground mines of the company.
Mine VI new vertical shaft construction site