Course Outline

The first part of this course looks at providing a concise overview of the basic generic factors that are involved in any underground mining system. The second part of the course deals with some actual ore bodies and how the generic basic factors were applied to arrive (in most cases) at safe, productive and profitable mines.

Generic factors – an analysis of underground mining systems

Geometry of the deposit

• What does it look like in 3-D, size and shape?

Geology of the deposit

• What sort of rocks are in the ground?
• What are the ore body rocks?
• What are the hanging wall rocks?
• What are the footwall rocks?
• Narrow vein, wide vein, massive?

Resource modelling

How do you fill in the gaps between different drillhole data?

Resource/reserve estimation and statutory requirements

• Can you trust the data?
• Reporting resources and reserves to the stock exchange
• The Joint Ore Reserve Committee (JORC) reserve
• The bankable feasibility study

Surface infrastructure and services

What’s needed on top to look after the underground?

Access to the underground

Declines, vertical shafts, conveyor belt inclines, second means of egress and escape, ladder ways

Ventilation to the underground

• Primary fresh air
• Secondary fresh air
• Return airways
• Refuge chambers and fresh air bases
• Emergency response management

Pumping and dewatering

Ground control and mine seismicity

• In situ rock stresses
• Rock mass quality
• Blasting damage
• Hydraulic radius
• Ground support

Overview of underground equipment

Mine planning understood

• Ore Characteristics – are you a salesman?
• Location, location, location
• Infrastructure priorities
• Putting costs and prices in context
• Which is best hematite or magnetite – the big picture
• How global projects are linked

Mining methods review – evaluating the costs and benefits of each method

Unsupported underground mining methods
Room and pillar, air leg mining, sub level stoping with pillars

Underground mining supported methods
Cut and fill, open stoping with backfill, backfill

Underground mining caving methods
Sub level caving, block caving, panel caving

Case study analysis section

Overview

Now the fundamentals have been taught and revised, this part of the course will aim to entrench this new information through the assessment of a select group of operating mines.

The goal for this case study session is to give participants an opportunity for the first half of the course sink in.

What better way to learn than to see how theory has been applied to real projects; where it has worked, and where it hasn’t.

Even better, the instructor will provide his insights and perspectives on how better decisions could have been made; what could have been done differently now there has been the chance to reflect.

The mining projects discussed will be selected from the list below, depending on the group on the day. They have specific relevance to the theoretical concepts taught.

• What is the best mine design?
• What is good? What is bad?
• What worked, and what didn’t?
• What should have been done?
• Taking into account production requirements, what methods have the most potential?
• Technically yes, but profitability wise, no – how do we make the best decision?
• What can we learn from this?

List of mines under case study

• Ridgeway gold mine- Sublevel caving to block caving
• Northparkes copper gold mine – Block caving
• Kanowna Belle gold mine – Open pit to underground large open stopes with backfill
• Argyle diamond mine – Open pit to block caving
• Telfer Deeps gold mine – Sublevel caving
• Olympic Dam copper gold uranium – Large open stopes with backfill
• Leinster nickel mine – Open pit to sublevel caving to block caving
• Lancefield gold mine – Sub level stoping with backfill
• Daisy Milano gold mine – Airlegging to mechanised back to airlegging
• Sons of Gwalia gold mine – Airlegging to open pit to sublevel stoping with backfill
• Mt Isa copper lead mine – Open stopes with backfill