Sample Collection Protocol

All sampling at Elouera Colliery was undertaken over a 1.8 km section of roadway from the mine portal to a point where height restriction issues made it impossible for the 4WD fire-protected vehicle (Figure 6.1) to travel any further into the mine. Comparisons were made to current NSW Department of Mineral Resources approved flameproof transportation vehicles (Figure 6.2). Three separate flameproof vehicles were tested in order to ensure any bias due to age or maintenance condition was minimised.

Figure 6.1

ACARP Project C6042 Prototype Fire-Protected Vehicle

Figure 6.2

The selected section of roadway provided a useful test venue as it required several stops for section lights and included a steep incline between coal seams. All vehicles were driven by the same operator following normal mine operating procedures and all vehicles operated on the same fuel supply. A standard driving schedule was devised to simulate a vehicle undertaking delivery duties within a section of the mine. Testing for ambient contaminants was performed while vehicles were driven to the above schedule.

This process was repeated over a period of approximately 10 days until sufficient samples were collected.

6.6 EXPERIMENTAL RESULTS

The raw exhaust of the 4WD prototype vehicle and three current transportation vehicles was analysed for diesel particulate at torque stall conditions using the R&P 5100 DP analyser. The results are presented in Table 6.4.

Table 6.4

Raw Exhaust Analysis – Diesel Particulate

Vehicle Engine Rated Power (kW)

Organic Carbon (mg/m3₎ Total Carbon (mg/m3₎ Elemental Carbon (mg/m3₎ Elemental Carbon (g/kWhr) 4WD Prototype Toyota 1 Hz (OHC-PCNA) 95 4.7 11.4 6.7 0.02 Unit No. 114 KIA 6-247 50 5.1 26.4 21.3 0.11

Unit No. 133 KIA 6-247 50 8.6 30.0 21.4 0.11 Unit No. 327 KIA 6-247

(supercharged) 70 6.7 22.3 15.6 0.06

Gaseous emissions in the raw exhaust were also measured under torque stall conditions, the results of which are presented in Table 6.5.

Table 6.5

Raw Exhaust Analysis – Gaseous Emissions

Vehicle CO ppm NOx ppm CO2 %

4WD Prototype 320 500 6.5

Unit No. 114 1,450 260 11.5

Unit No. 133 530 270 11.0

Unit No. 327 220 350 10.5

Sampling for atmospheric DP concentrations was conducted inside the driver’s cabin of all four vehicles using SKC disposable sampling heads. The results provided in Table 6.6 are the average of at least two samples collected at the same time.

Table 6.6

Ambient Diesel Particulate Concentrations Inside Driver’s Cabin of Vehicles

Vehicle Carbon (µg/mOrganic 3₎

Elemental Carbon (µg/m3₎ Total Carbon (µg/m3₎ 4WD Prototype 223 19 242 Unit No. 114 169 183 345 Unit No. 133 224 123 367 Unit No. 327 284 58 342

Sampling for ambient gaseous concentrations was also performed in the driver’s cabin of all four vehicles. Peak concentration values for all contaminants tested are presented in Table 6.7.

Table 6.7

Ambient Gas Concentrations (Peak Values) Inside Driver’s Cabin of Vehicles

Vehicle CO ppm NOppm NO2 ppm

4WD Prototype 5 2.5 Not detected

Unit No. 114 34 3.5 Not detected

Unit No. 133 7 4.2 Not detected

6.7 DISCUSSION OF RESULTS

Examination of the results in Table 6.4 clearly indicates that the raw exhaust elemental carbon levels generated by the Toyota 1 Hz engine (0.02 g/kWhr) are substantially lower than that generated by all KIA 6-247 engines (0.06 – 0.11 g/kWhr). This conclusion needs to be considered with a level of caution as the 4WD prototype vehicle did not have an exhaust system similar to that on the KIA vehicles. The 4WD prototype achieved compliance with statutory temperature requirements (150°C) by the injection of water into the exhaust immediately below the exhaust manifold. The KIA engine vehicles were fitted with a standard water bath which may place increased backpressure on the engine.

Nevertheless, there is sufficient evidence to suggest that the 4WD prototype vehicle is discharging a lower level of elemental carbon into the general mine atmosphere. This conclusion is strongly supported by the results of ambient monitoring in the driver’s cabin of all vehicles (Table 6.6).

These results indicate that the atmospheric elemental carbon concentrations within the driver’s cabin of the 4WD prototype vehicle (19 µg/m3_{) are significantly below that within the driver’s}

cabin of the KIA engine vehicles (58 – 183 µg/m3_{). This represents}

a reduction of between 67 – 90% dependent on the engine involved.

The peak ambient gaseous concentrations do not appear to show any distinctive difference for carbon monoxide between the 4WD prototype vehicle and two of the KIA engine units. The third unit (No. 114) had a major carbon monoxide peak which is consistent with the high concentration of carbon monoxide in the raw exhaust (1,450 ppm).

On the positive side, this level of carbon monoxide was present for only about 3-4 minutes (Figure 6.3) which is the approximate time taken to traverse the incline between coal seams, suggesting that a “plug” of exhaust was travelling at the same speed as the vehicle. Attempts to repeat this condition were unsuccessful, with the highest subsequent carbon monoxide level recorded being 12 ppm and levels during the rest of the monitoring exercise (several hours) were typically below 5 ppm.

0 5 10 15 20 25 30 8:33 :33 AM 8:34 :33 AM 8:35 :33 AM 8:36 :33 AM 8:37 :33 AM 8:38 :33 AM 8:39 :33 AM 8:40 :33 AM 8:41 :33 AM 8:42 :33 AM 8:43 :33 AM 8:44 :33 AM 8:45 :33 AM 8:46 :33 AM 8:47 :33 AM 8:48 :33 AM 8:49 :33 AM 8:50 :33 AM 8:51 :33 AM 8:52 :33 AM 8:53 :33 AM 8:54 :33 AM 8:55 :33 AM Ca rb on Mono xi de (p pm )

Travelling from mine portal

Between seam incline

Figure 6.3

Quest MultiLog 2000 Graph of Carbon Monoxide Concentrations – Unit No. 114

The ambient peak concentrations for nitric oxide did not appear to display any relationship to the raw exhaust concentrations, with the vehicle with the lowest raw exhaust oxides of nitrogen level (4WD prototype) having the lowest ambient concentration.

6.8 CONCLUSIONS

Over the last 10 years emissions from engines produced for over-the-road diesel vehicles have reduced significantly.

Unfortunately, this major advance has not transferred to the Australian underground coal mining industry due to the market size, intrinsic safety issues and mine engineer preference.

While the benefits of new technology engines have been known for some time, little data exists to demonstrate the benefits of this advance in technology over the engines currently used within the Australian coal mining industry. The data generated within this project demonstrated that under mining conditions an engine of newer design has the potential to reduce atmospheric elemental carbon concentrations by up to 67 – 90%. Similarly, raw exhaust elemental carbon analysis indicates similar significant reductions.

While these results are encouraging, the true situation will not be clear until a new technology engine (eg electronic controlled) passes intrinsic safety approvals and is fitted to a normal underground vehicle. Comparisons between vehicles of this type and current mine vehicles, using principles similar to that described above, will be very useful. The data generated from the current research project suggests that such a process will produce positive benefits and is worthy of pursuing.

7.

TOWER COLLIERY RESEARCH GROUP EXPOSURE