1. Mineral Exploration Tel: (07) 3316 2531 Fax: (07)3295 9570
Mineral Exploration
This PowerPoint provides an introduction to the technology around mineral exploration. It provides reasons for exploration and includes factors that need to be considered before a mine is developed.

2. Why explore for minerals?
Demand for minerals (especially from the developing world)
Demand for products made from minerals.
Teaching Tip:
Background Notes:
Demand for minerals and the products they produce requires the constant discovery of new deposits. This is especially the case for the developing countries such as India and China who are seeking the same high standard of living and industrialisation evident in the west
In an average lifetime each Australian will use:
200 tonnes of coal (plastics, heating, electricity, bitumen)
litres of oil (fuel, heating)
55 tonnes of limestone (building cement)
50 tonnes of iron ore (iron and steel products)
12 tonnes phosphate (fertilisers, soap, detergents)
4 tonnes lead-zinc ore (protects steel from rusting, car batteries, sound proofing)
Predicted demand for copper world wide
Source: Courtesy of Queensland Government Dept Mines and Energy

3. The search begins Difficult to find Deeper locations
Grades of ore are lower
Image Description
Satellite images provides some indication of where a mineral deposit may lie. It is followed by other remote sensing techniques such as aerial exploration.
Teaching Tip:
Background Notes: Over time the more obvious and accessible minerals have been discovered and developed with the result that today the search is tougher and more complicated. Even when a deposit is found there is no guarantee it will be economically significant and worth mining
Satellite Image

4. Is it worth mining? Size and quality of the deposit
Geographical location
Depth at which it is found
Environmental impact
Marketability
Teaching Tip:
Background: The above points need to be taken into consideration when exploration for a particular mineral is being considered. Discuss the relevance of each point.

5. Aerial Exploration Satellite Imagery Magnetometers Teaching Tip.
Background: Satellite imagery, magnetometers maps and computers are tools of the modern explorer. (More details to follow.)
Source: Queensland Resources Council

6. Source: Queensland Government Dept Mines and Energy
Aerial Geophysical Surveys
Measure the earth's magnetic and gravitational and electrical properties
Teaching Tip:
Background:
Magnetometers and electro-magnetometers can be used on the surface or flown over often inaccessible areas in aircraft. The information is processed by a computer to prepare aero-magnetic and gravity maps of an area.
Source: Queensland Government Dept Mines and Energy

7. Source: Queensland Government Dept Mines and Energy
Geophysicists
Measure:
the earth’s magnetic conditions
resistance to the electric current
local gravitational effects
Teaching Tip:
Background: the colours represent the magnetic intensity of the earth; the reds and pinks indicate areas that are more magnetic than others and hence may indicate a mineral deposit.
Source: Queensland Government Dept Mines and Energy

8. An anomaly Can be more recognisable following computer manipulation
Can indicate a viable spot which maybe worth mining
Anomaly
Teaching Tip:
Background:

9. Land based exploration
Teaching Tip:
Background:
After analysing all the information to date a decision is made to determine if the area warrants further exploration through a land based survey. After permission is granted by the government and consultation with landowners and indigenous representatives occurs, a team will begin field work to further explore an area. Geological samples are collected by hand trenching or shallow drilling and analysed. More geophysical data in the area is gathered adding to the information.
Source: Queensland Resources Council

10. Geochemists Analyse the mineral content of soil, water, vegetation
Provide indications on what lies beneath the surface.
Teaching Tip:
Background: Once remote sensing or aerial surveys have been completed and if there are positive indications a closer examination of the earth will follow. This involves a geologist or geochemist collecting samples from the earth e.g. leaves, roots from trees as these may reveal traces of minerals that could indicate a deposit in the area.
Source: Queensland Government Dept Mines and Energy

11. Surface Drilling Teaching Tip: Background:
If the signs are positive, a decision is made to investigate further beneath the surface. This involves expensive drilling using diamond drill bits to extract core samples which are later analysed. Diamond drill holes can be more than 1.5 km deep. In the remote and dry areas of Australia where most exploration is now occurring drilling can be expensive, difficult and time consuming. But the drill core provides the first solid evidence of what may be underground. Many drill hoes may be needed to cover the areas being explored. Additional drill holes are made if the findings are positive. Data from each hole helps to form a clear picture of the mineralisation below the surface. If enough minerals are found concentrated in an area it is called an orebody.
Source: Queensland Resources Council

12. Geologists
Collate and analyse information from maps, geophysical aerial surveys, satellite images and previous surveys
Use information from the geological survey sections of state government mines departments, Geoscience Australia
Teaching Tip:
Background:
To accurately determine where geological anomalies occur
Source: Queensland Resources Council

13. Further studies Economic Assessment Exploratory Shaft Ore Analysis
Teaching Tip:
Background:
A company must be certain a viable orebody exist before it commits the millions of dollars needed to develop a mine. Studies involving every possible economic aspect must be made. Also an exploratory shaft could be sunk to extract a sample of ore for metallurgical testing. Analysis of these ores helps to determine the most suitable processes and plant equipment needed to recover the minerals from the ore.
Image courtesy of CSIRO

14. The final decision! Commercial Viability Environmental Affects
Community support
One in two hundred exploration sites becomes a mine
Image Description
Queensland setting for metal distribution; Mount Isa - base metals, Iron oxide copper gold
Georgetown Region – gold, porphyry copper, tin, Hodgkinson Basin – Palmer River gold
Charters Towers – epithermal gold
Major terrains of interest to explorers are in north and central Queensland
Teaching Tip:
Background:
The final decision is made on the commercial viability of the project and on the possible affects of the environment and community. The proceeds of the sale of the minerals must outweigh the cost of mining and concentrating the mineral. It can take years from discovery to commencement of mining operations. The owners of the land are kept informed of the work being carried and any progress made during the exploration phase. One in two hundred exploration sites becomes a mine.
Distribution of metal deposits in Queensland
Source: Queensland Government Dept Mines and Energy