9.2.2: Directional Terms

9.2.2: Directional Terms

The directional terms are quite useful and not too difficult to remember. Let me give you an example to illustrate these terms before I give you the formal definition. Imagine that we are all in a big classroom, and the classroom represents the mined out opening. This classroom has rows of chairs and then near the front of the room there is a table on which I lay my books and materials, and then we have a chalkboard on the front wall. I stand behind the table to lecture. There is a door into the classroom on the rear wall. Got the picture?

Ok, let’s imagine that we are mining in the direction of the chalkboard, i.e., we are advancing in the direction of the chalkboard. We’re going to drill holes into the chalkboard, load the holes with explosives, blast, and load out the broken material. We’ve just made the classroom bigger! The chalkboard where we drilled and blasted is known as the face or working face. It is also known as the breast. The act of mining in this horizontal direction is known as breast stoping.

Now, let’s suppose that I’d like to make the classroom higher rather than longer. So, I am going to drill holes into the ceiling, load the holes with powder, shoot them, and load out the broken material. When I advance in this upward direction, it is said to be overhand stoping. Similarly, if I wanted to enlarge our classroom to a lower level, I would drill down into the floor, blast, and load the broken material. When I advance in a downward direction, it is called underhand stoping.

Finally, I can squeeze one last example out of this classroom setting to help you understand the terms inby and outby. These two terms are very useful to state a relative position. Typically, the relative position is between the working face and the entrance to the mine or some portion of the mine. In our classroom that we are pretending is a mine opening, we have a working face (chalkboard wall) and an entrance (the door in the rear wall). Remember the table near the front of the room. If I am standing behind the table, close to the chalkboard, I am standing inby the table, and you are sitting outby the table. If we had a video camera set up in the fourth row back, the students in rows one through three would be sitting inby the camera, and the students sitting in row five to the back of the room would be sitting outby the camera.

This business of inby and outby may seem a little strange, but these words are extremely useful. There is for example, a regulation that prohibits miners from working inby the last row of roof bolts. Or another that allows certain electrical equipment to be used only if it is outby the last open crosscut. Hopefully, with this example, the following terms will be clearer.