Abstract: This invention relates to methods for quickly and accurately detecting the presence of rare earth minerals which can be performed in the field. An ore sample to be tested for the presence of rare earth minerals is contacted with both a basic reagent, preferably containing an alkali metal, and with a halide acid such as hydrochloric acid. Once the treated ore sample is dry, it is examined under a shortwave ultraviolet light for fluorescence of a red-orange color. If rare earth minerals are present, fluorescence of a red-orange color will occur. If no rare earth minerals are present, no red-orange fluorescence is observed. The sensitivity of the disclosed methods to rare earth minerals may be varied by altering the basic reagent to permit the user to "zero in" on the most concentrated source of rare earth minerals.

Abstract: A method and apparatus for testing a subsurface formation for the retention of a fluid where energy is passed through the formation, including inserting a test fluid into the formation in the path of the energy, the test fluid having properties of mobility corresponding to those of the fluid to be retained and properties affecting in a detectable manner the energy passed through the test fluid in the formation; and sensing the energy affected by passage through the test fluid in the formation to determine the retention potential of the formation.

Abstract: A method and apparatus for locating and evaluating geothermal sources of energy wherein it is known that the earth has electrical currents and that these currents are reflected in electrostatic voltage gradients above the earth with magnitudes in proportion to the magnitudes of adjacent subterranean geothermal sources, characterized by detecting the voltage gradients; individually recording the voltage gradients; and evaluating the recorded gradients for determination of the location and potential of adjacent sources of geothermal energy.

Abstract: A method and apparatus for detecting the thermal characteristics of a subsurface formation in situ wherein a borehole has been drilled from the earth's surface, including inserting a known volume of cryogenic material into the borehole to a predetermined position in the formation to produce a zone of cooling in the formation thereabout; conducting test energy, subject to change by passage through a cooled medium of conduction, from a predetermined position in the borehole below the zone of cooling along a plurality of paths through and laterally of the zone to the surface; sensing the changes in the energy incident to passage through the zone at predetermined positions on the surface laterally of the borehole; calculating the volume of the zone from the known and acquired information to determine the thermal conductivity of the formation; and noting the time required for the known volume of cryogenic material to be boiled off by the formation to determine the latent heat of the formation.