1. Control of Mining and Milling of Uranium and Thorium Ores by Fred Searls, Jr. Mr. Searls is a mining engineer and geologist and is di- Introduction Chapter I of the report of the Scientific and Technical Committee of the United Nations Atomic Energy Commission1 indicates agreement of competent representatives of the nations on the Commission that two naturally occurring elements, uranium and thorium, which are found in the earth's crust in significant quantities, play a unique role in the production of atomic energy. It has been generally held, and is agreed in Chapter III of the Scientific and Technical Committee report, that control of atomic energy will require control of the raw materials from which these two elements can be produced. It is further agreed that, while significant diversion at this stage is more difficult and also less immediately dangerous than at later stages, no type of control can be certainly and fully effective unless it begins with production of these raw materials and is maintained with increasing rigor as they are processed to nuclear fuels. As noted in the report of the Scientific and Technical Committee, the danger of theft and petty diversions increases as the material moves through the process of conversion from a raw ore, usually of low uranium or thorium content, to purified metals or salts, and increases further and more rapidly as these are converted to nuclear fuels. The present article does not discuss control of uranium and thorium as metals or as purified compounds suitable for use alone or "A First Report on the Scientific and Technical Aspects of the Problem of Control," September 27, 1946. in conjunction with other substances for the production of atomic energy. There will arise numerous and serious questions relating to the sources of production and the distribution of such products. This article purports to deal only with the measures of control that would be technically required in the case of mining and milling. The assumption is made that there would be an international control authority which would itself be above question or suspicion, so that adequate control by it would mean security as far as that could be insured by the measures discussed. The purpose here is merely to outline briefly the nature of the technical control that would be required to insure that responsible heads of the international control authority could themselves know that all of these raw materials being produced in the world during any given period of time were accounted for. The basic information will be available only after all the nations make complete disclosure of their resources in the ores of these metals. Then there will be required a knowledge of stocks of these metals and their salts, of materials in process, and of quantities allocated and delivered to known locations and projects for research, developmental or industrial uses. Mining of Ores Uranium has been found and produced in substantial quantities from ore in place, having a content from less than 1% to as high or higher than 10% content of U3O8. Thorium, on the other hand, has been found in place only in a very low-grade ore and, it is believed, will be obtained commercially only from alluvial accumulations, in which a degree of concentration has already occurred by natural processes. It is probable that by far the largest part of future uranium and thorium ore production will be from deposits in which their compounds occur mixed with other substances, themselves valuable in the resources and economies of the countries in which such deposits occur. In many countries, such deposits are owned by private individuals or corporations, and in several instances development and mining of such deposits have been placed under national regulation or restriction. It will be evident that control of production of these raw materials can be applied differently depending on whether the deposit is in one or the other of the following two groups: (1) The deposit is idle or is producing only uranium or thorium ores. (2) The deposit is being currently operated for its content of other substances, and is producing and either saving or wasting the uranium or thorium content. This is called a by-product operation. Control of Ores As regards the first group of deposits, control is relatively simple. A determination will be necessary as to which deposits are to be worked and which are to remain idle. This would, in effect, make the "approved" mine operation legal and all others illegal. The easiest control of ores is to insure that such quantities of them as are not required remain in the ground. Such control can only be reached under a world-wide plan of production, allocation, and use of these ores, without which it is believed that all effort for control of these ores and metals would be futile." In regard to the control of both groups of deposits, it is believed that this can best be attained by an agreement which provides that all production of these ores must be immediately sold to a single purchasing agency, which would be the direct agent of an international control authority. Such a purchasing agency would be especially necessary in the control of by-product operations. This agency would require wide powers and would be able to acquire very substantial quantities of these ores. The source of its funds and the disposition of its purchases are outside the scope of this article. To achieve adequate control over the production of uranium and thorium in this way, the international control authority should have the following powers and duties: (1) It must require that all uranium or thorium ores immediately upon separation shall be sold to the purchasing agency. The agency inust exercise such inspection and supervision,as to insure that the entire production from each deposit is covered by such transactions. This will require authority from and support by the national government in each of the countries where mining or concentrating operations are conducted. In some cases, the governments or their citizens will be interested in other products from the same ores. (2) The international control authority must determine and have the staff, authority, money, and technical ability to sample and correctly estimate the output from the mine, the input to the mill, concentrator, or other type of plant, and the tailings or discard. Daily inspection and check sampling will be required to prevent diversion. (3) The international control authority should also systematically sample the ground or developed ore deposits, so as to have an accurate and independent knowledge of the quantity and grade of ore to be produced, or the volume and content of ground handled in alluvial 'For a detailed discussion of the inspection of uranium mines, see "A Conference Report on International Inspection of Radioactive Mineral Production," by the Committee on Inspection of Raw Materials of the Carnegie Endowment for International Peace, February, 1946. operations. This information would constitute a check on daily recovery estimates obtained from heads and tails samples. (4) A referee system, similar to that in constant use in settlement of differences between smelting companies and their shippers, should be provided. Such referees, as well as the employees of the international control authority, should be assured free access to all operations at reasonable times. The referee system will be essential when any operation fails to balance by reasonable agreement of the ore estimates and head samples with the recovery plus tailings. Procedure, after such failure to obtain reasonable balance or agreement, becomes a matter of enforcement. (5) Provision would have to be made for penalizing the illicit possession of and traffic in uranium and thorium ores, as has been done in the case of several countries for the illicit possession of diamonds and gold. The purchasing agency as one section of the international control authority would have no customers, but would merely pass on its purchases to refineries of this authority. Appropriate provision would be required for taking care of normal commercial uses outside the field of atomic energy. Processing of Ores The materials obtained from the deposits would, in the case of thorium, be a monazite sand, containing some admixture of other heavy sands, and would contain 5% or more of thoria. In the case of uranium mines, the material obtained would be impure uranium oxide, mixed with other heavy tailings and varying widely in uranium content. The material from by-product operations would be impure salts of uranium. For the production of uranium or thorium, the processing required at the mine or deposit is normally limited to the various methods of concentration, but a purer product would be obtained in certain cases from smelters or other pyro-metallurgy installations. Control of the plants accepting these materials for further processing is beyond the scope of this paper. However, it may be pointed out that the processes so far used in reduction of these materials to pure uranium, or to those salts of uranium used for isotope separation or other purposes, do not require plants of great size. Their control is discussed in the next article. |