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lakes, and fine, laminated clays and chemical and organic lacustrine sediments accumulated in the center of the lakes. As the result of the continual shift in the shoreline the fluviatile clays and silts interfinger or intertongue with the lacustrine sediments around the basin edges. The basin centers, are, therefore, the best areas in which to find the greatest continuous sequences of lacustrine sediments.

Senator HART. Mr. Wayland, I wonder if it is possible for the Department to reproduce, perhaps without the photos, these exhibits to which you are making reference and which we have here for our record. It would be helpful I know and we would appreciate it if it can be done.

Mr. WAYLAND. Those particular four exhibits? Yes, sir. One of them is reproduced, the one on the right closest to you is figure 1, in the back of my statement, and the other three figures I have here for my information just as a Xerox of a print and I have just the one copy which I will

OIL SHALE RESOURCES

OF THE GREEN RIVER FORMATION
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Senator HART. Then, we will

Mr. WAYLAND. I can simply give them to you.
Senator HART. For the record.

Mr. WAYLAND. How many copies would you prefer?
Senator HART. Just one is enough for our purposes.

Mr. WAYLAND. I will just leave these three with you. These are not exact duplicates. I notice a slight difference. These were taken a little earlier.

Mr. WAYLAND. Since the exploratory drilling to date suggests that the Piceance Creek Basin in Colorado contains the largest tonnages of the organic-rich lacustrine sediments, and that most of these are in the Parachute Creek member of the Green River formation, let us look at the stratigraphic sequence and character of this member briefly. The Parachute Creek member ranges in thickness from 850 feet on the margin in the Piceance Creek Basin to a maximum of about 1,800 feet.

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As shown on figure 2, and also more or less in the left hand of the panels there, it consists of an upper oil shale zone containing small masses of saline minerals and a thicker, lower oil shale zone containing more abundant saline minerals. Within the upper oil shale zones is a very rich oil shale unit called the Mahogany zone, sometimes the Mahogany ledge, a term derived from the fact that a polished surface simulates old mahogany in a remarkable manner. This unit generally weathers to a sheer cliff where it is exposed at the surface. The Bureau of Mines has conducted its experimental mining in the Mahogany zone, and most retorting experiments have been performed on oil shale from this unit.

The lower zone of the member differs in general from the upper zone in that, near the basin center, several sodium carbonate minerals as well as common salt-halite, sodium chloride-are commingled with the oil shale. Near the basin center the saline-rich zone attains a thickness of nearly 900 feet. Sodium carbonate minerals occur intimately intermixed with the organic material in the individual oil shale beds throughout most of this zone. The known halite beds are near the top of this sequence.

Information available from the limited number of deep core, drill holes indicates that the oil shale beds in the bottom part of the upper zone of the member have had much of their soluble sodium minerals leached and removed by ground water in a zone several hundred feet thick. The rocks in the leached zone are commonly broken and brecciated. Units of soft, punky, and bleached oil shale as well as solution cavities are common. I emphasize the solution cavities. This zone is apparently water bearing, and active removal of water-soluble minerals may still be taking place, according to latest studies by survey geologists Hite and Dyni.

In the Green River Basin of Wyoming the member of the Green River formation that most closely resembles the Parachute Creek member is named the Wilkins Peak member. The beds making up the bulk of the Wilkins Peak member were deposited in a lake at relatively low stages, perhaps at only one-third of its maximum extent. This shrinkage gave rise to the great abundance of saline minerals, trona included.

Although these lacustrine sediments in the Green River formation in the various basins are relatively young in geologic age, they are compacted, tilted, and locally folded in all of the basins. In the Piceance Creek Basin of Colorado the downwarp is assymetric, with very slightly dipping beds in the south and west and more steeply dipping beds in the north and east. Several subparallel, northwest-trending folds include the Piceance Creek dome in the northeastern part of the area, and just to give you a scale, as mapped at the surface, this structure has a 200-foot closure in 10 miles of length.

The oil shale beds, their composition, that make up so much of the Parachute Creek member (Colorado), and Wilkins Peak member (Wyoming) of the Green River formation cannot be regarded strictly as a typical shale. Shale is normally defined as a fine-grained sedimentary rock composed primarily of clay minerals such as kaolinite or illite. The oil shale beds were deposited out from the shoreline in bodies of water that contained some of these common clay materials in suspension but also contained plants and animals or debris from land

plants as well as much dissolved calcium, magnesium, and sodium carbonate. The oil shale beds of interest to us today are, therefore, better described as chemically precipitated dolomitic marlstone rich in organic matter and in sodium carbonate minerals.

To digress just a little bit here, dolomitic marlstone would be the magnesium and calcium carbonate while the sodium carbonate goes into the other minerals of greater interest to us here today. Not mentioned here, but of interest is the fact that during the period that the lakebeds were being deposited, there was volcanic activity close enough so that clouds of volcanic ash fell into the lake water and the ash was gradually altered to some zeolitic materials such as analcite which is potentially of economic interest, to. But not yet.

Continuing, the mineral grains in the rock typically range from clay size to silt size. Some soluble minerals like nahcolite have grown to larger sizes as nodules after the sediments were deposited. Digressing again, this is a well-known process. It occurs while the rocks are still quite wet during forming and consolidating and there are chemical changes that take place in such rocks after deposition, but before consolidation.

The organic fraction of the deposits is mostly finely divided solid matter, sometimes called kerogen.

When this rock is heated in a retort, part of the solid organic matter is converted to oil and hydrocarbon gas, and part remains in the shale as coke or char.

Shale units that yield a few gallons to about 65 gallons of oil per ton are distributed throughout much of the Green River formation in the three States. In general, the central parts of the Piceance Creek Basin and the Uinta Basin contain thick, rich oil-shale sequences that grade to thinner and leaner oil shale at the basin margins. Somewhat thinner and generally lower grade oil shale in the Green River Basin and Washakie Basin, Wyo., also show decreases in grade toward the basin margins. I should add that this is the present state of our knowledge, to be improved naturally as we get more information.

On the quality, quantity, depth, and thickness, we find that the major resources of current interest are the parts of the deposits in which oil shale beds are found ranging in thickness from a few hundred to 2,000 feet and averaging from 15 to 30 gallons per ton in yield of shale oil. And, by recurring interest here, I mean in a gross way, the current interest of your committee, we feel.

Known parts of the deposits that yield 25 to 65 gallons of oil per ton contain about 450 to 500 billion barrels oil equivalent in the Piceance Creek Basin, Colo., about 90 billion barrels in the Uinta Basin, Utah, and about 30 billion barrels in the Green River Basin, Wyo., or a total of about 600 billion barrels. Approximately 160 billion barrels of oil equivalent is in units more than 25 feet thick averaging 30 to 35 gallons of oil per ton and lying less than 1,000 feet below the surface. Assuming that about half of this higher grade, more accessible shale could be mined under present conditions, about 80 billion barrels of shale oil is considered recoverable by demonstrated mining and retorting methods. I do not say recovered economically but this can be recovered.

Known oil shale deposits that yield 10 to 25 gallons of oil per tonthis is lower grade-contain about 800 billion barrels of oil equivalent

in the Piceance Creek Basin, Colo.; about 230 billion barrels in the Uinta Basin, Utah; and about 400 billion barrels in the combined Green River Basin and Washakie Basin, Wyo.

For comparison, the American Petroleum Institute news release of April 3, 1967, places the Nation's proved recoverable reserves of liquid hydrocarbons at 39.8 billion barrels, including 8 billion barrels of natural gas liquids. Proved recoverable reserves are those you find which experience indicates can be recovered from known reservoirs under existing economic and operating conditions.

Possible upward revisions of the shale oil resources of the Green River formation may equal what is already known. Larger, undiscovered, better grade resources will perhaps be found in the deeply buried parts in the Uinta Basin.

OTHER MINERAL PRODUCTS ARE IN OIL SHALES

Nitrogen compounds and sulfur, which normally occur in the organic matter of shale, but which are undesirable in fuels, are extracted as useful byproducts in some of the European oil shale industries. Other materials such as vanadium, uranium, copper, sodium (trona), and phosphatic material are also present in some deposits of oil shale in sufficient amounts to be of commercial interest as coproducts. And some industries in Europe have produced lime, brick, or lightweight aggregate from the ash of the shale.

In this country the Green River formation has very interesting possibilities for coproduct development. In all three States the Green River sediments include considerable deposits of sodium carbonate minerals. Trona, a sodium carbonate, is presently being mined in large tonnages in Wyoming, but has not been confirmed in the Green River beds elsewhere. This mineral is an important natural source of soda ash. Another sodium carbonate mineral, nahcolite, is widespread and abundant in Colorado and Utah but rarely reported in Wyoming. Shortite, a sodium calcium carbonate, is abundant in Utah and Wyoming but rare, if present at all, in Colorado.

Of particular interest is the discovery in the Piceance Creek Basin of large quantities of the sodium carbonate mineral, dawsonite, which also contains alumina. It has been almost a mineralogical curiosity in the world heretofore. First recognized in the Green River formation by Charles Milton of the U.S. Geological Survey in 1958, its extensive occurrence was discovered in recent drilling in the Piceance Creek Basin in connection with operations under Federal sodium prospecting permits.

The dawsonite shows great vertical and areal distribution in the northern part of the basin. The thickness of a continuous dawsonitebearing interval in 18 drill holes is reported to range from zero just south of the Rio Blanco County line, which is shown here in the exhibits, to as much as 760 feet toward the center of the basin. Nahcolite shows greater areal distribution than dawsonite, but like dawsonite it becomes more abundant toward the center of the basin.

In addition to these deposits, concentrations of uranium and phosphate occur in thin persistent zones in several areas of Green River beds in Wyoming and Utah. Localities of high uranium and phos

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