Final answer:
To calculate the amount of rock that must be mined for every 10kg of copper produced, we need to consider the thermal energy contained in each cubic meter of rock at a certain depth and the percentage of mass converted to energy in nuclear reactions.
Step-by-step explanation:
In order to determine how many tonnes of rock must be mined for every 10kg of copper produced, we need to use the given information. From the reference, we know that each cubic meter of rock at a depth of 4 km contains 250 MJ of thermal energy. Additionally, we are told that only 0.08% of mass is converted to energy in nuclear reactions. Therefore, we can calculate the amount of rock that needs to be mined by using the formula: (10kg of copper / (0.08% * mass converted to energy)) * 250 MJ / 1000000 kg = x tonnes of rock.