Mining-Prospecting Dictionary

• Igneous: Refers to rocks of molten or volcanic origin.
• Impervious: Said of a rock that does not permit the passage of fluids under the pressure conditions ordinarily found in the subsurface.
• Impregnated: Rocks or minerals saturated with some other substance.
• Incline: A rising slope.
• Incrustation: A coating or crust on a rock.
• Indicated value: The preliminary value determined for a placer sample, before it is adjusted or corrected for known variables.
• Infill Drilling: Diamond drilling at shorter intervals between existing holes, used to provide greater geological detail and to help establish reserve estimates.
• Initial Margin: Customers' funds required at the time a futures position is established, or an option is sold, to assure performance of the customer's obligations.
• In-the-Money Option: Call option - if the futures price is above the strike price. Put option - if the futures price is below the strike price.
• Intercept: That portion included between two points in a borehole, as between the point where the hole first encounters a specific rock or mineral body and where the hole enters a different or underlying rock formation.
• Intrinsic Value: The absolute value of the in-the money amount - that is, the amount that would be realized if an in-the-money option were exercised.
• Intrusion: A mass of rock that has been forced into or between other rocks.
• Iridescence: Display of colors by diffraction of light.