Ore can be divided into oxide ore and sulfide ore according to chemical composition. A: 正确 B: 错误

Ore can be divided into and lean ore according to grade.

Which of the following is the ore breaking methods?( ) A: Artificial ore breaking B: Mechanical and hydraulic ore breaking C: Rock drilling and blasting D: The other three options all meet the requirements

Which of the following statements is true?( ) A: The other three options all meet the requirements B: Leveling refers to leveling the surface of ore retention pile after local ore releasing. C: Prying roof means that the roof and two sides of loose ore rock should be pryed off when the site is leveled. D: Gravity ore drawing is generally adopted for local ore releasing

The iron ore is one of the chief exports of( ).

Which of the following is the most abundant solid mineral in the seabed?( ) A: Manganese nodule B: Nickel ore C: Copper mine D: Cobalt ore

有两个并发执行的进程P1和P2，共享初值为1的变量x。P1对x加1，P2对x减1...ore x，R2两个操作完成后，x的值

What are the benefits of tilting the layered steps? ( ) A: Easy to separate mining of ore and rock and improve ore quality B: Convenient for transportation equipment operation C: Convenient for mining equipment operation D: Ease of layering

According to the passage, how did Bessemer method make the mass production of steel possible A: It directed air at melted iron in a furnace, removing all impurities. B: It slowly heated iron ore then stirred it and heated it again. C: It changed iron ore into iron which was a substitute for steel. D: It could quickly find deposits of iron ore under the ground.

( ) is not a kind of major bulk. A: iron ore B: phosphates C: bauxite D: cement