Table 6. Average Reflectance Values for the Samples from Each Coal Type with Time and Temperature.

	residence time (min)	temperature (°C)
		700	900	1050
Antioquia	10	2.23	4.28	4.92
	30	2.82	4.59	5.08
	120	3.96	4.86	5.34
	540	5.57	5.27	5.61
Cundinamarca	10	2.31	5.05	5.94
	30	3.43	5.50	6.51
	120	4.18	5.79	6.73
	540	5.71	6.34	7.33
Patia	10	2.33	4.51	5.11
	30	2.69	4.68	5.43
	120	3.42	4.83	5.71
	540	4.28	5.04	6.12
Valle	10	2.28	5.44	6.21
	30	3.71	5.86	6.62
	120	4.65	6.15	6.61
	540	6.18	6.66	6.93