Mar 23 2011

The pass rate for Paper 1 has been very poor for many years and questions have been asked of students as well as the examiners. Some common problems have been identified from the last five exams and Johan Hanekom, director of Middindi Consulting, explains what students can do to pass this paper.

Paper 1 ensures that the minimum theoretical knowledge that is required to perform the required rock engineering functions, are well understood by the student. It can not simply be ignored or rushed over, it requires a lot of studying to ensure that all concepts are well understood.

The last papers have shown that students do not study hard enough.

It takes time

The largest concern is that students do not allow for enough study time. This paper sets the scene for all rock engineering knowledge in all the other papers and it is required that you spend the right amount of time on it. It is called BOC – butt-on-chair.

There is no easy way but to study, and if an examination paper is well constructed, it should not allow a person who has only studied old papers to pass. You must understand it all to be a good rock engineer. Make sure you spend the time on it that justifies its importance. For example, it has no use trying to design a mine, if the understanding of stress and state of stress is non-existent.

Student responses have often shown that they do not have adequate knowledge of the stress-strain behaviour of a rock sample in a press. How then can the student understand why certain rocks behave differently on his mine, or the impact of confinement on the behaviour of rock or a pillar?

The tendency that minimum effort is acceptable is just not acceptable when you are responsible for people’s lives. I don’t accept it a medical practitioner makes a mistake, especially if it happens to someone close to me. If I know he passed his degree with only 60%, it enrages me to think he could be totally ignorant of 40% of all the things that could go wrong.

How can we then justify it to merely pass the RE examinations, when we are supposed to design safe working places underground? Paper 1 is but one step in the direction to understand the theory and is critical to how you practice your profession. That does not mean that we all will get 100%, but that should be our aim.

Understand maths and physics

The knowledge and understanding of basic mathematics and physics is critical. You can not solve stress rotation problems if you do not understand basic trigonometry and know how to calculate angles using trigonometry functions.

Understand how your calculator works. How many places after the comma does it rounds up or down, when to work in radians and when in degrees, how to change the subject of an equation, basic understanding of graphs, etc.

Basic mathematical rules such as orderly execution and recording of calculations are essential. Many mistakes are made because the consecutive lines in a calculation were misaligned (equal signs not underneath each other), writing of numbers and variables are so confusing that the student loses the plot during the calculation.

• The use of SI units and the changing of units from Pa to MPa are non-existent in most cases. You must record and show the units in each calculation. Working with 46MPa, but showing only a 46, without indicating that it is MPa or showing (x10⁶ Pa) is incorrect and result in confusion as soon as KPa and MPa values are mixed in a question.

• In mine design designing for a support resistance of 100N/m² is not the same as 100kN/m², therefore units are really critical and should be displayed at all times. Not showing them or incorrectly showing them is unacceptable in engineering.

• Knowledge and understanding of forces, stresses, strains, energy, etc as basic physical concepts is essential. How to analyse forces are different to analysing stresses. It must be clear where these come from and how they are to be applied.

This paper is part of an engineering qualification and one would expect an engineer to have a good understanding of maths and physics, as that is what his subject is founded on.

Read the questions

Reading questions is critical to ensure correct and well planned answers. The student should know exactly what information is given and what answers are expected.

Do not go off on a tangent because you think you know where the question is going. List the given, list the requested. Think about how you would progress from the one to the other and then only attempt to answer.

Unplanned answers show that you don’t have a clear thought process, therefore you have no real idea how to solve a problem. You run in a direction and hope it takes you somewhere.

Experienced examiners spot this easily and it often makes the difference when they are faced with a result that is close to the pass mark. Well planned and thought through answers get you the nod, whilst unclear, rushed, think-I-know answers show that you are not yet ready.

Engineering is a logical, well planned and executed subject. It it weren’t we would have had many more car accidents and plane crashes because the engineers designed on the back of a tissue, using no calculator, some wishful thinking and hoping that somebody would find it acceptable.

Understand the concepts

Always understand the limitations and areas of application of all concepts. Sometime you may think that something is applicable, but it may not be, and even though you arrived at an answer, the application of the concept was incorrect.

When theory is asked, be aware of the marks allocated. In most cases, simple regurgitation of knowledge requires more facts for similar marks to questions where you must do some thinking or analysis. Give a minimum of two facts per mark, use sketches and equations as far as possible. But do not go overboard with information and write pages for a few marks, look for and show the most important information on each issue.

When you discuss theoretical concepts, show units, arrows, axis names, etc, do not provide small, hand drawn sketches to explain a concept.  Do not perform a Mohr circle analysis using hand drawn sketch – it has to be accurate. Use the necessary tools to show that engineering thinking is backed by engineering presentation.

Know what you know

These issues are but a few things that you should look at and give attention. You are attempting to show that you have the required knowledge of the theory to be a competent rock engineer, with the emphasis on engineer. You must therefore be able to show that your thinking processes, your knowledge and the application thereof is at an acceptable level.

If you won’t walk over a bridge that was designed in the same way as you answered a question, then you know you have not shown competence. Therefore, test your own knowledge when you prepare, look at your prepared examples, ask yourself whether you really understand what you are doing and then only attempt the paper with confidence