The Unexpected Temperature
For most of the dig, the expectations that the researchers had about the temperature aligned with what they found. This was the case for the first 10,000 feet. However, they noticed something strange after this. The level of heat climbed faster than they assumed it would! As they approached their target, the temperature of the borehole was 356 °F or 180 °C, which is 186 °F or 80 °F higher than they had in mind.
There Was More
That was not the only thing that they found out either. Researchers also saw that at that depth, the rock was much less dense than they thought it would be. This made it react with the very high temperatures in unpredictable ways. They had no choice but to abandon their mission since the equipment would not withstand the heat. It was already 1992 by the time that they did so, 22 years after they started digging.