Searching for Iron Ore

Introduction

The element iron is found in many metals you see every day. It is often combined with other elements to make very strong and rust-resistant metal alloys. To make steel, carbon is added to iron to increase its strength. Chromium can be added to iron to make stainless steel which is resistant to corrosion.

Most natural iron deposits are in the form of iron ores such as hematite and magnetite. These iron ore formations were deposited between 1.8 and 2.6 billion years ago. While they are sometimes found at the surface, many are located underground making them more difficult to find. Most iron ores are ferromagnetic, meaning they are attracted to magnets and can become magnets themselves when placed in a magnetic field. Over time, the Earth’s magnetic field has magnetized these ancient iron ore formations. This unique characteristic allows geologists to locate iron ore formations with a magnetometer, an instrument that measures magnetic field strength. As the magnetometer passes over the surface of the Earth, an iron ore formation will show up as a magnetic disturbance similar to the pattern a magnet would make. This not only locates the iron ore formation, but gives a good estimate of its size as well.

In Part I of this experiment, you will use a Magnetic Field Sensor to investigate the magnetic pattern made by a sample iron ore formation represented by a magnetized washer. In Part 2, you will use a Magnetic Field Sensor to scan a model search area for a buried iron ore formation. The buried formation will show up with a magnetic pattern similar to the sample in Part I.

Objectives

In this experiment, you will

• Use a Magnetic Field Sensor to map the magnetic field of a sample iron ore formation.
• Use a Magnetic Field Sensor locate a buried iron ore formation.
• Explain your results.