As nations have awakened to their need of mineral raw materials and to the recent rapid depletion of these materials, they have been naturally led to inquire how long the reserves may last, and to consider prevention of waste and the more efficient use of materials, with a view to planning more prudently for future national supplies. The first inquiries seemed to reveal such shortage of mineral supplies as to call for immediate and almost drastic steps to prevent waste, and possibly even to limit the use of certain minerals in the interests of posterity.
More careful study of the problem, as might be expected, revealed new factors and greater complexity. The conservational idea has a wide sentimental appeal, but the formulation and application of specific plans meet many difficulties. In its practical aspects the problem is now a live one, the solution of which is requiring the attention of mining men, engineers, geologists, economists, and public officials. It is a question which is coming more and more into the field of actual professional practice of the economic geologist.
It is our purpose to indicate the general nature of the conservation problem. We may assume agreement to the desirability of preventing waste, of making a wise present use of mineral products, and of striking a proper balance between the present and future in their use. Nature has taken many long geologic periods to build up these reserves. We, of the present generation, in a sense hold them in trust; they are entailed to our successors. With this general thought in mind, how shall we proceed to formulate definite plans for conservation?
An initial step is obviously a careful taking of stock. With increasing knowledge of mineral resources, it is becoming apparent that early estimates of supplies were too low. Many of these estimates failed to take into account mining to great depths, and wide use of low-grade ores, rendered possible by improved methods; and especially they failed to put sufficient emphasis on the probabilities of new discoveries to replace exhausted supplies. Early predictions have already been upset in regard to a number of mineral resources. The recognition of the general fact that the world is far from explored in two dimensions, to say nothing of three, of the fact that known geologic conditions do not yet indicate definite limits to the possibilities of exploration for most mineral resources, and of the consequent fact that for a long time in the future, as in the past, discoveries of new mineral deposits will be roughly proportional to the effort and money spent in finding them,—which means, also, proportional to the demand,—makes it impossible, for most of the mineral resources, to set any definite limits on reserves. It is comparatively easy to measure known reserves; but a quantitative appraisal of the probable and possible reserves for the future is extremely difficult. Successive revisions of estimates have, with but few exceptions, progressively increased the total mineral supplies available. The result is that the time of exhaustion has been pushed far into the future for most of the important minerals, thus minimizing the urge for immediate and drastic conservational action, which followed naturally from early estimates of very limited supplies. For both coal and iron, supplies are now known for hundreds or even thousands of years. For oil and lead, on the other hand, the reserves now known have a life of comparatively few years, but the possibilities for successful exploration make it probable that their life will be greatly extended. Notwithstanding this tendency to lengthen the exhaustion period, the limits of mineral resource life are still small as compared with the life of the nation or of civilization,—and the fundamental desirability of conservation is not materially affected.
It is not easy to predict the rate of production for the future. At the present rate of coal production in the United States, the supplies to a depth of 6,000 feet might last 6,000 years; but if it be assumed that the recent acceleration of production will be continued indefinitely into the future, the result would be exhaustion of these supplies in less than 200 years. It is generally agreed that exhaustion will come sooner than 6,000 years, but will require more time than 200 years. The range between these figures offers wide opportunity for guessing. It is supposed that per capita consumption may not increase as fast in the future as in the past, that possibly an absorption point will be reached, and that there will be limits to transportation and distribution; but how to evaluate these factors no one knows. In the case of some of the metallic resources, such as iron, the fact that the world's stock on hand is constantly increasing—losses due to rusting, ship-wrecks, etc., being only a small fraction of the annual output—suggests that a point will be reached where new production will cease to accelerate at the present rate and may even decline. But again, the factors are so complex and many of them so little known, that no one can say how soon this point will be reached.
For the immediate future, there is little to be feared from shortage of mineral supplies in the ground. The difficulties are more likely to arise from the failure of means to extract and distribute these supplies fast enough to keep up with the startling acceleration in future demand indicated by the figures of recent years. The speed and magnitude of recent material developments in many lines cannot but raise question as to whether we have the ability to understand and coödinate the many huge, variable, and accelerating factors we have to deal with, or whether some of the lines of development may not get so far ahead of others as to cause serious disturbance of the whole material structure of civilization. Coal alone, which now constitutes a third of our railway tonnage, may with increased rate of production require two-thirds of present railway capacity. Will railway development keep up? It may be noted that national crises and failures in the past history of the world have seldom, if ever, been due to shortage of raw materials, or in fact to any failure of the material environment.
In its early stages the conservation movement in this country concerned itself principally with the raw material. Later there came the recognition of the fact that conservation of raw materials is closely bound up with the question of conservation of human energy. The two elements in the problem are much like the two major elements in mineral resource valuation (see pages 329-330). If in saving a dollar's worth of raw material, we spend two dollars worth of energy, it naturally raises question as to the wisdom of our procedure. It might be wiser in some cases to waste a certain amount of raw material because of the saving of time and effort. It might be better for posterity to have the product of our energy multiplied into raw material than to have the raw material itself. The valuation of these two major elements of conservation is again almost impossible of quantitative solution. We do not know what is the best result to be aimed for. We cannot foresee the requirements of the future nor the end toward which civilization is moving—or should move. The extravagance of the United States is often contrasted unfavorably with the thriftiness of Europe. When considered in relation to raw materials alone, there seems to be basis for this charge. When considered in relation to the product of human energy into raw materials, the conclusion may be far different; for the output per man in the industries related to mineral resources is far greater in the United States than in Europe. In the case of iron, it has been estimated that the output per man in the United States is two and one-half times as great as in the rest of the world. Which is best in the true interests of conservation, we are not yet able to see.
Our view of what is desirable in the way of conservation depends somewhat on the limitations imposed by self-interest or location. By devoting ourselves exclusively to one mineral resource, we might work out a conservation program very disadvantageous to the best use of some other mineral commodity. We might take steps to conserve chromite in the United States which would have a disastrous effect on the iron and steel industry. We might conserve coal by the substitution of oil, when the procedure is hardly warranted by the supplies of oil available. We might work out a program for the United States which would not be the best conservational plan for the world as a whole, and which would ultimately react to the disadvantage of the United States. The wisest and most intelligent use of mineral resources seems to call unquestionably for their consideration in their world relations, rather than for a narrow interpretation of local requirements.
DIFFERENCES BETWEEN PRIVATE AND PUBLIC EFFORTS IN CONSERVATION
It appears that a wide range of effective conservational practices has resulted solely from the effort to make more money through more efficient operations, and this is likely to be true in the future. Many improvements in mining, grading, sorting, concentration, and metallurgy of minerals, to yield larger financial returns, are coming naturally through private initiative, under the driving power of self-interest.