(Description)

and may be desired and designated by the party of the first part, for the agreed price per foot sunk, as shown and set forth in the following scale of prices, at different depths up to feet, and in accordance with the further terms and conditions herein contained. Provided, however, that in case the drilling of any well shall be stopped by the party of the first part for any cause after it has been begun, that the party of the first part will pay the net cost of moving the drilling outfit to any other place on the said property where another well is to be started, in addition to the amount earned for the number of feet sunk in accordance with the said scale of prices per foot and that should work be stopped on any well for any cause, after a depth of feet has been sunk, then the said party of the second part shall move the rig at his own cost and expense to the place designated by the party of the first part. That in case of abandonment of any well or wells for any cause the party of the second part will pull and remove, in a careful manner, all casing, pipe and fittings used in said well or wells that can be got out by a reasonable and faithful effort by the use of all appliances and tools ordinarily used in performing such work.

That all casing, pipe and shoes of the proper sizes necessary to be used in the well or wells will be furnished and delivered on the ground by the party of the first part and shall be of such sizes as such party may select, and the same shall be properly inserted and used in the wells by the party of the second part and carried to the bottom, if possible, without diminishing the size except in cases where it is found absolutely unavailable after the use of under-reamers and other appliances, as may be necessary and proper for keeping the whole in proper shape.

That in case a body of asphaltum be encountered at any considerable depth and it is found impossible after a faithful and reasonable effort so to do that it can not be drilled through nor penetrated by the use of any of the known tools and appliances, then the said well will be considered as completed and a settlement made in full for the depth drilled according to the said scale of prices; provided, however, that the party. of the first part shall have full and free right and privilege to use and operate the machinery and outfit of the party of the second part at his own cost and expense for a period not to exceed

until satisfied that the hole can not be sunk any deeper.

or

That in case oil, gas or asphaltum shall be found at any depth in any well and the party of the first part shall elect to stop drilling in such well, the party of the second part shall properly test the well and leave the same in condition ready for the pump or other working appliance before moving the rig and outfit away.

It is understood by and between both parties hereto that this contract is for a total of feet of hole or wells, and that the party of the second part agrees to put down any one hole to a total depth of feet, if the ground is such that it can possibly be done, by reasonable effort, or that he will stop the drilling of any well at any depth, as directed by the party of the first part and in accordance with the said scale of prices per foot sunk, and the terms and conditions herein contained.

That the party of the first part will pay, or cause to be paid, to the party of the second part the amount earned for each foot of hole sunk in accordance with the said scale of prices at times and as follows,

to wit:

An advance sum of dollars, when the rig and outfit are on the ground and ready to commence the work of drilling; -- per cent of the amount earned as per scale when the well has been sunk to a depth of feet and a like.‒‒‒‒ - per cent of the amount earned at the completion of each feet until the well is either completed or abandoned, or the work stopped by the party of the first part, when the balance in full shall be paid, after deducting the said advance payment of

Done in duplicate, the day and year first above written.

dollars.

NOTE.

Federal and state leases on oil and other mineral lands will be covered in a future issue of 'Mining in California.'-Editor.

NOTE ON ANDALUSITE FROM CALIFORNIA.

A NEW USE AND SOME THERMAL PROPERTIES.*

By ALBERT B. PECK.1

The andalusite described here is found at an elevation of 10,000 feet on the southwestern slope of White Mountain in the White Mountains of the Inyo Range, Mono County, California. The deposit itself is located across a canyon about two miles east and north of an occurrence described by Knopf. The andalusite reported by Knopf, however, is at present of no commercial value owing to the fact that it carries too large amounts of quartz.

MINERALOGY.

Occurrence and Physical Properties.

The main mass of the andalusite rock can probably best be described as coarse granular, and it is generally of a gray or light pinkish brown color. On exposed surfaces the color is yellow brown due to oxidation. The texture of the rock varies greatly. Many large fragments show a very distinctly coarse radial or columnar structure, definite rough crystals four or five inches in length being noted. At the other extreme are smaller areas which have a very fine granular texture, sugary in appearance and very friable, breaking down readily into a fine sand. While the material is generally quite compact there are occasional large cavities in the mass, and in these are sometimes found excellent groups of large coarse crystals at times reaching five inches or more in length. The color of the material shows variation also. Crystals are generally white on the exterior but when broken show directly beneath the surface a pale apple green color. Columnar or radial masses also show green or gray color but granular masses are usually white, gray, or pinkish brown. This latter color is in reality due to inclusions of scattered rutile grains or crystals, as can readily be observed when examined microscopically.

Crystallography:

The crystals appearing in cavities are generally rather simple in form but of uncommon habit for andalusite. This probably accounts for the fact that of all those to whom a group has been shown, no one has as yet named the crystals as andalusite. The crystals are usually covered with a thin white coating which is dull and somewhat rough, so that accurate measurements of the crystal angles are impossible. Contact goniometer measurements, however, show sufficiently close relation to the theoretical values to establish the forms present. The crystals usually occur in more or less parallel groups terminated at one end only and are also attached to each other by the prism faces so that the prism zone is generally only partly complete.

Read before the annual meeting of the Mineralogical Society of America at Washington, D. C., December, 1923. To appear in the American Mineralogist, June 1924. Mineralogical Laboratory, University of Michigan.

2

Journal Wash. Acad. Sc., 7, 549 (1917).

Figure 1 shows the form of a typical crystal. The predominant prism is k(210) and the end of the form is terminated by the dome r(101). Measurements of the angles are as follows:

The prism faces on the larger crystals are somewhat rounded, hence the variation in the angles noted for this form. Faces of the smaller

r

k

FIG. 1

crystals, however, give values close to those calculated for the form. Owing to the fact that the ratio of a:b in andalusite is nearly 1:1, the angles for the forms (210) and (120) are very similar. It was necessary therefore in this case to make a thin section parallel to the base and determine the position of the optic plane. This was found to be in the short diagonal and being parallel to the a-axis, the prism then is established as k(210). It follows that the dome is r(101) and not s(011), these two forms also being very similar in their angles.

Chemical Composition.

On the whole the rock material is a rather pure andalusite with comparatively small amounts of several other minerals. During mining, the material is constantly checked by specific gravity determinations on

a Jolly balance. Samples are taken over the face of the working and if favorable, the material is broken out, carefully hand selected, and sacked. Generally it runs at least 75-85 per cent andalusite upon microscopic examination. A typical chemical analysis from a sample representing a carload shipment recalculated to an Al,SiO, basis will show over 90 per cent Al,SiO.. Such an analysis follows:

The fact that the chemical analysis generally shows higher Al,SiO, than is indicated by the microscopic examination is due to the very general presence of corundum in the material. In no case do the associated minerals assume any large proportion over any considerable area although locally they may occasionally outweigh the andalusite.

Associates.

The associates of the andalusite are also deserving of mention, especially because several are counted among the less common minerals. Lazulite is perhaps the most unusual mineral associated with the andalusite. It occurs in small blue-green veinlets or masses scattered through the mass. Optically it shows a distinct light blue pleochroism. Chemical analysis usually shows small amounts of P2O, present in the rock.

Pyrophyllite is another uncommon mineral found with the andalusite. It occurs in crusts of radial fibers on the walls of cracks or as radial masses in small cavities. Owing to its chemical composition, as soon as its water is lost it takes on nearly the same composition as andalusite and hence can hardly be considered as an impurity.

Muscovite also occurs in much the same manner as pyrophyllite and is somewhat more abundant but at no time reaches large proportions. It occurs in distinct plates, usually in divergent groups.

Corundum is a rather common associate of the granular andalusite and is usually deep sapphire blue in color. It is generally in small scattered plates or grains but occasionally may form lenses two or three inches in size. According to observation thus far it is always blue in color. In a few instances crystals of andalusite with blue corundum centers have been noted. For manufacturing purposes a small amount of corundum is favorable to the neutralization of the effect of any excess quartz in the rock.

Rutile is a rather constant associate, largely as microscopic inclusions. in the andalusite. At times small free crystals can be found. The constant association of rutile and the blue color of the corundum would seem to confirm the theory that the color of sapphire is due to the presence of TiO..

Pyrite is sometimes found locally, especially near open veins. When near the surface it has often weathered leaving a stained and porous rock.