EJERCICIOS DE VENTILACIÓN MINERA

1. La oxidación lenta de rocas fragmentadas libera un volumen de 0.15 pie3/min de SO2. Si el límite de este gas es de 5 ppm, ¿cuál será el caudal de aire fresco necesario para diluir este gas a su límite permisible?

Q0=

0.15∗0.30483

605∗10−6

=14.158m3/ s

Q0=15m 3/s

2. Las labores profundas de una sección minera tiene problemas de calor. Las mediciones psicométricas del aire dieron los siguientes resultados: Carga térmica: 3000 KW Temperatura del aire: td/tw=79/65 °F Presión barométrica: 0.075 lb/pie3

En opinión del supervisor, el problema puede ser controlado utilizando ventiladores. Si el criterio usado para diseñar el sistema de ventilación es el de mantener la temperatura por debajo de 82°F, ¿Cuál debe ser la capacidad del ventilador?

Q0=q1−2

W∗(h2−h1)= 3000∗56.870.075(45.8−30)

=143974.6835 ft3 /min

Q0=¿144000 ft3 /min

3. Estudio de caso:

Para claridad de la explicación, estos estudios de caso implican una vía aérea única en lugar de una secuencia de ramas, aplique el software CLIMSIM (Demo) para analizar el flujo de calor subterráneo del presente caso interpretando los resultados gráficos, alimentando la siguiente información:

GENERAL BRANCH INFORMATION:

BranchName: Ramp Description: MainRamp Output interval: 20m

AIRWAY PROPERTIES:

Length: 500m Depth in: 450 m Depthout: 530m Area: 8.75 m2 Perimetro: 12m Friction: 0.014 Kg/m3 Wetness factor(%): 0.20 Age at inlet: 350 días Age at outlet: 70 días

VENT AT INTAKE:

Quantity: 30 m3/s Pressure: 106 KPa Dry Temp: 35°C

Wet Temp: 26°C

ROCK PROPERTIES:

VRT at inlet: 42°C Geothermal step: 40m/°C Conductivity: 4.5 W/m°C Diffusitivity: 2.15 m2/s*E-6

HEAT SOURCES DATA:

Spot heather at: 175m

Sensible heat: -200kw

Latent heat: 0.00 kw

Diesel at: 100m

Power Output: 175kw, utilization: 60%, WFR=7

Linear heat at: 250m, Length: 250m

Sensible heat: 230 kw

Latente heat: 0.00 kw

Distance(m)

Dry Bulb (°C)

Wet Bulb (°C)

Pressure(KPa)

Moisture(g/Kg)

Density(Kg/m3)

Humidity(%)

Enthalpy(KJ/Kg)

Sigma Heat

(KJ/Kg)

Dry Wall (°C)

VRT (°C)

MST(°C)

ET(°C)

WBGT(°C)

Strata QL

(kW)

Strata QS

(kW)

HTC(W/m2°C)

0 35.00 26.00 106.000 16.44 1.186 48.55 77.35 75.56 35.3 42.0 29.90 25.80 28.70 0.00 0.00 23.87720 34.78 26.03 106.033 16.57 1.188 49.53 77.46 75.66 35.1 42.1 29.89 25.68 28.65 11.28 -9.02 23.84940 34.57 26.05 106.066 16.70 1.189 50.50 77.58 75.76 34.9 42.2 29.88 25.56 28.61 10.99 -8.65 23.82860 34.38 26.08 106.099 16.82 1.190 51.45 77.70 75.86 34.7 42.2 29.87 25.45 28.57 10.71 -8.29 23.80880 34.19 26.11 106.132 16.94 1.191 52.37 77.81 75.96 34.6 42.3 29.87 25.35 28.53 10.44 -7.95 23.788100 34.01 26.14 106.164 17.06 1.192 53.27 77.93 76.07 34.4 42.4 29.86 25.24 28.50 10.19 -7.61 23.770120 37.90 28.19 106.197 18.93 1.176 47.61 86.76 84.53 38.1 42.5 31.28 28.72 31.10 9.94 -7.29 24.324140 37.64 28.21 106.229 19.07 1.177 48.65 86.86 84.61 37.9 42.6 31.28 28.60 31.04 12.29 -10.52 24.298160 37.40 28.23 106.262 19.21 1.179 49.67 86.97 84.70 37.6 42.6 31.28 28.49 30.98 11.95 -10.09 24.273180 31.68 26.90 106.295 19.35 1.201 68.71 81.36 79.18 32.2 42.7 30.05 23.95 28.33 11.62 -9.68 23.649200 31.63 26.93 106.328 19.42 1.202 69.18 81.50 79.31 32.2 42.8 30.07 23.93 28.34 6.28 -2.99 23.640220 31.58 26.97 106.362 19.49 1.202 69.64 81.64 79.43 32.1 42.9 30.09 23.91 28.35 6.18 -2.83 23.632240 31.54 27.00 106.395 19.56 1.203 70.08 81.77 79.56 32.1 43.0 30.11 23.89 28.36 6.10 -2.68 23.623260 31.75 27.10 106.428 19.64 1.202 69.50 82.18 79.95 32.3 43.0 30.19 24.13 28.49 6.02 -2.53 23.643280 32.21 27.26 106.461 19.71 1.201 67.97 82.84 80.59 32.8 43.1 30.32 24.59 28.75 6.16 -2.67 23.690300 32.66 27.42 106.495 19.78 1.199 66.54 83.51 81.24 33.2 43.2 30.46 25.03 28.99 6.53 -3.08 23.736320 33.10 27.58 106.528 19.86 1.198 65.19 84.17 81.88 33.6 43.3 30.59 25.46 29.24 6.89 -3.48 23.781340 33.53 27.74 106.561 19.95 1.196 63.93 84.84 82.52 34.0 43.4 30.72 25.86 29.47 7.24 -3.87 23.826360 33.95 27.89 106.594 20.04 1.195 62.75 85.50 83.16 34.5 43.4 30.85 26.25 29.71 7.58 -4.25 23.869380 34.36 28.05 106.627 20.13 1.194 61.63 86.16 83.80 34.9 43.5 30.98 26.62 29.94 7.92 -4.61 23.912400 34.76 28.20 106.660 20.23 1.192 60.58 86.83 84.44 35.2 43.6 31.11 26.98 30.17 8.24 -4.95 23.954420 35.15 28.35 106.693 20.33 1.191 59.59 87.49 85.08 35.6 43.7 31.23 27.32 30.39 8.56 -5.28 23.995440 35.53 28.51 106.726 20.43 1.190 58.66 88.15 85.72 36.0 43.8 31.35 27.65 30.61 8.87 -5.60 24.036460 35.90 28.66 106.759 20.54 1.189 57.78 88.82 86.35 36.4 43.8 31.48 27.97 30.83 9.17 -5.90 24.076480 36.26 28.81 106.791 20.65 1.188 56.95 89.49 86.99 36.7 43.9 31.60 28.28 31.04 9.47 -6.18 24.116500 36.62 28.96 106.824 20.77 1.187 56.16 90.15 87.64 37.1 44.0 31.72 28.58 31.26 9.77 -6.45 24.155

Diesel heat source at 100 m, sensible heat = 147.68 kW, latent heat = 149.47 kW Spot heat source at 175 m, sensible heat = -200.00 kW, latent heat = 0.00 kW Linear heat source starts at 250 m, length = 250 m, sensible heat = 230.00 kW, latent heat = 0.00 kW Strata heat totals: sensible heat = -146.46 kW, latent heat = 220.40 kW Other heat totals: sensible heat = 177.68 kW, latent heat = 149.47 kW Metabolic rate = 200 W/m², Skin temperature limit value = 36.00 °C