The miners in both areas were familiar with the gravity element of the GBM, but washing pans were not used in the areas before the intervention started (in Kalinga, they had never seen a washing pan before). Borax was a known and readily available chemical in the mining areas. After amalgam burning, a bit of borax was often added and burned to make the surface of the gold shine. Many miners found it hard to believe that borax can be used as a “gold catcher” in the same way as mercury, until they had the technique demonstrated. Still, compared with the amalgamation method, the GBM was perceived as more complex.
When using the new method, the miners observed immediately that they did not have to buy mercury, but it could not be recognized right away that the extraction rate with GBM can be higher as it takes some practice to refine the method. Also, the gold content of the ore varies considerably from sack to sack, and many miners preferred the safe amalgamation method with rich ores and were more likely to experiment with GBM with a less rich ore. Neither short- nor long-term health benefits were immediately recognizable.
When using the new method, the miners observed immediately that they did not have to buy mercury, but it could not be recognized right away that the extraction rate with GBM can be higher as it takes some practice to refine the method. Also, the gold content of the ore varies considerably from sack to sack, and many miners preferred the safe amalgamation method with rich ores and were more likely to experiment with GBM with a less rich ore. Neither short- nor long-term health benefits were immediately recognizable.
