Page 237 - Advanced Mine Ventilation

216 Advanced Mine Ventilation

Figure 13.1 Carbon monoxide blood saturation [2].

The main danger from CO is due to its toxicity. It has a great affinity for the hemo-
globin in the blood with which it forms a permanent bond dcalled carboxyhemoglo-
bin (COHb). If the blood saturation by COHb increases, various symptoms become
apparent, and they are listed in Table 13.2. The rate of saturation depends on CO level
in mine air. If the CO concentration is 1% (10,000 ppm), death can occur in a minute.
Death can also occur at 70%e80% blood saturation with COHb (Table 13.1).
Fig. 13.1 shows gradual blood saturation as a function of CO concentration and
exposure time [2].

Table 13.2 Gradual CO Poisoning of Blood and Symptoms

Blood Saturation
(% COHb) Symptoms
5e10 First noticeable effect, loss of some cognitive function.
10e20 Tightness across forehead, possible headache.
20e30 Headache, throbbing in temples.
30e40 Severe headache, weakness, dizziness, dimness of vision, nausea and
vomiting, and collapse
40e60 Increased likelihood of collapse and unconsciousness, coma with
intermittent convulsions.
60e70 Coma, possible death.
70e80 Respiratory failure, death.