By reference to the opinion of the court below, reported in 20 F.Supp. 153, 154, we avoid needless repetition. It will there appear that in a suit for infringement brought by plaintiff, assignee of Patent No. 1,968,008, granted July 24, 1934, to George A. Chapman and John W. Littleford, for “Concentration of Minerals”, the court held the patent valid and infringed. Thereupon defendant took this appeal and, as infringement is admitted if the patent is held valid, the sole question here involved is validity. After hearing and due consideration had, we find ourselves in accord with the court below. We might well affirm on the comprehensive and able opinion of the trial Judge, but in view of the importance of the case and the earnest contention of counsel, we here record some of the facts and reasons which logically force us to affirm.
The accepted practice of the art prior to the patent is thus described by Judge Nields:
“The principal source in the United States of calcium phosphate used as a raw material by the fertilizer and chemical industries is the so-called Pebble Phosphate Rock Field of Florida. Under an ‘overburden’ of earth and sand varying in depth from 5 to 25 feet, lies a stratum or ‘matrix’ of phosphate mineral varying in thickness from 3 to 12 feet. The business of the Florida phosphate industry is to mine this phosphate mineral and to remove from it the silica and clay. ‘Phosphate concentrates’ thereby produced are sold to the fertilizer and chemical industries. The overburden is removed by huge scoops operated by powerful machinery and piled in long ridges. This leaves the stratum of phosphate material exposed. It is then mined hydraulically. This hydraulic mining disintegrates the stratum of phosphate ore by means of powerful streams of water. The mixture of ore and water is pumped to a ‘washing’ plant through an iron pipe a foot in diameter.
“The phosphate washing plant separates the silica and clay from the phosphate particles and screens out the coarser phosphate material. Much of the clay is washed out. A large proportion of the phosphate mineral is of such a size as to be easily separated from the gangue by washing and screening. About 50 per cent, of the phosphate is thus removed in the form of a finished product suitable for market.
“The remaining 50 per cent, of the phosphate passes through the screens in the washing plant along with the major part of the silica and other impurities. Until about 1927, this finer material, known in the industry as ‘washer waste,’ ‘washer tail-ings,’ or ‘debris,’ was regarded as uncon-centratable and was sent to waste. Such washer waste was allowed to flow away frequently into pits from which phosphate mineral had been mined. The solids settled there. Such ‘dumps’ are scattered over the Florida phosphate . field. They contain many millions of tons of phosphate in the *792form of fine phosphate particles mixed with silica and clay. The loss involved in sending to the dumps 50 per cent, of the phosphate was fully understood.”
In the art prior to the patent in suit shaking tables were well known and their possibilities used, but all known use of them secured no more than 50 per cent, recovery of phosphate, while the remaining 50 per cent, passed into 'the dump. The recovery of such percentage was due to the fact that they separated phosphate from clay, silicon and the like only where the component particles varied widely in size, shape or specific gravity, and that they did not and could not. separate the residue which consisted of the minute particles of. phosphate, silicon, clay and the like, which did not differ widely in size, shape or specific gravity.
The gist of plaintiff’s patent was adding to the table practice of the old art a cooperating factor which revolutionized the aft and made possible a very large recovery'of phosphate from the minute particles in the dumps. In that regard the court held:
“Shaking tables had been used in the art of ore concentration only for the concentration of minerals in which the valuable particles and the gangue particles differed widely in specific gravity. In such, cases, separation on a table had depended upon this difference in the specific gravities of the ore particles to be separated. In such table treatments, the valuable particles were the heavier and settled on the table between the riffles and passed off at the end of the table. The lighter gangue particles stratified on top of the heavier metalliferous particles and were washed by the water flowing across the table over the riffles and into the launder along the lower long side of the table.' Chapman and Littleford knew that the difference in the specific gravity of phosphate and of the gangue was so slight that no separation could be based on it. Before they fed the oiled phosphate pulp to a shaking table they did not know what would happen. The phosphate being slightly heavier than the gangue, there was no certainty about the operation. To their surprise the slightly heavier phosphate particles in the form of loosely-bonded ' agglomerates - stratified above the gangue and were washed across the table and the gangue. was guided by the riffles to the end of the table. Before t-he experiment was tried it-was impossible for any one in the light of the knowledge of the art to say it would be successful.
“There was no experience in the prior art for the phenomenon of skin flotation of the phosphate particles on the surface of the water flowing across the table. The bursting of the bubbles in some of the loosely-bonded agglomerates as they came to the surface of the water in passing over the riffles and the consequent skin flotation of some of the phosphate particles in these agglomerates was an entirely new and unexpected phenomenon.
“It is the loosely-bonded agglomerates-in the phosphate mineral pulp that caused, the separation of the phosphate from the-gangue on the table. Loosely-bonded agglomerates had never been recognized in. any pulp of any mineral. Chapman and Littleford discovered them in an oiled phosphate pulp and discovered the way to-utilize them for the separation of the phosphate from the gangue in that pulp.”
This surprising and unlooked for result the patent effected' through the element “adjusting the water content of the finely-divided ore to insure having all the particles thoroughly wetted and adding a selective flocculating agent to the ore.” In that regard the proof is that “the Chapman and Littleford process depends for its operation on the formation of loosely-bonded agglomerates which are mineral particles such as phosphate mineral particles fastened to minute air bubbles. These agglomerates are heavier than water but slightly lighter than the gangue.” And in answer to the court’s inquiry, “Do you find the loosely-bonded agglomerates in any process other than the patent in suit?” the defendant’s expert — and we find no-proof to the contrary — testified: “A. Of my own experience? Q. Among those here cited? A. No.” • Moreover in that, regard the court found that: “Chapman, and Littleford patent in suit covers a new method of concentration of minerals, particularly phosphate minerals, not' disclosed1, or suggested by the prior art. * * * Until the Chapman and Littleford process-in 1929 no one had concentrated phosphate mineral too small for screening and washing and too large for froth flotation.”
The novel use of the table is shown by what may be called the revolutionary-change of table operation ,in the fact that in the standard Wilfrey table, “the heavy concentrate grains going into the lower layers, and the lighter waste grains into-*793the upper”, while in the use of the table as affected by “adding a selective flocculating agent” was such that as stated in the specification “phosphate particles ride on the surface of the water, while silica and other impurities are wetted and tend to sink.”
That the process of the patent was a working surprise is shown by the evidence. In that regard the proof by plaintiff’s expert is, “Those loosely-bonded agglomerates were a revelation to me when I saw them in Florida. I was surprised to see the particular structure in question and to see how they were made use of in the process of the defendant and plaintiff alike.” Indeed it seems the defendant’s expert agrees therewith when, he says: “Either by reason of the stirring rod that was effected here, or by reason of the plunge of the material from the feed through into the tank, a surprising amount of air is entrained and much of it attached to the oiled phosphate particles.” How this phenomenal and unexpected result is effected and utilized is stated, for example, in representative claim 2 of the patent, which reads: “The process of concentrating phosphate ore which comprises adjusting the water content of the finely divided ore to insure having all the particles thoroughly wetted and adding a selective flocculating agent to the ore, mixing said agent with -the ore to form a thin film or coating of said agent on each phosphate mineral particle and to at least in part form loosely bonded agglomerates of said particles, then subjecting the mixture to agitative wet stratifying classification according to the relative settling values of the treated mineral and the gangue and gathering the phosphate in an overlying stratum.”
So far as the claims here in controversy are concerned, the element “a selective flocculating agent” is stated in claim 3; “adding selective agents to the thus wetted ore”, in claim 3; “a fraction of 1 per cent, of sodium soap and a fraction of 1 per cent, of petroleum oil”, .in claim 4; “a small proportion of soap and un-saponifiable oil”, in claim 6; “a small proportion of a soap-forming radical and alkali and an unsaponifiable oil”, in claim 14; and “a selective flocculating agent”, in claim 21.
At this point we venture to state our conjectural understanding of the phenomenal separation process, which undoubtedly takes place, and our physical reasons why it does occur. We start with the fact that while in the table practice of the old art a separation of the large phosphate particles, to the extent of SO per cent, was effected, yet there still remained unaffected a large quantity of mingled and.minute particles of phosphate and silicon, sand and clay. To the separation and recovery of these phosphate particles the patent is addressed.
As the agitation of the table proceeded, air bubbles formed which tended to rise to the surface. The “selected flocculating agent”, now for the first time used in tabling phosphate, also rose to the surface of the water and in its upward passage smeared or formed a scum or covering on the air bubbles. The silicon being an adsorbent, was not attracted to the oil coated air bubbles and, therefore, stayed in, or sunk to, the lowest' stratum. On the other hand, the phosphate particles, thoroughly wet and smeared with a coating of oil, and being attracted to the rising oil coated air bubbles, were by them buoyed to the surface of the water. The result was that as the shaking process proceeded, the phosphate or pulp particles were washed over the riffles or dam and were recovered, while the silicon, clay or gangue remained in the lower level, could not pass over the riffle and was carried to the dump.
As we view it, such action is disclosed in ' the patent specification, which says: “According to the present invention, the concentration is effected by procedures which may include skin or film flotation in which phosphate particles ride upon the surface of water while silica or other impurities are wetted by the water and tend to sink. * * * The process may be carried on or aided by table concentration wherein the silica, which tends to sink in the water flowing over the table, is carried off in the general direction of the riffles, while the phosphate particles, carried in or on the water flowing across the riffles of the table, are delivered to a concentrate launder, and are thereafter de-watered. The phosphate-bearing material is herein described as made easily amenable to such skin flotation or water-flowing separation or both by prior treatment, as with an alkaline substance, or with soap and oil, or with alkali and a saponifiable oil. Variations of treatment may produce skin flotation, water flowing separation with differential separation under wet stratifying conditions, or both. Where an oil is used the *794oil selectively coats phosphate particles, making them more amenable to separation.”
Referring to the specification, the court .held and found:
"This quotation- describes a new and unexpected phenomenon resulting from feeding to a shaking table oiled phosphate pulp. It was an original and inventive act to feed such oiled phosphate pulp to a shaking table for the following reasons:
"(1) It had never been the practice to treat oiled or otherwise conditioned pulp of any mineral on a shaking table. It was the practice of the art to treat on a shaking table only pulps composed of water and mineral untreated by any agents.”
Seeing then the disclosure of the patent specifications was novel and of high' value and as the proofs sh.ow, the question remains did it involve invention? We are clear that it did. In addition to the prima facies incidentally awarded to the grant of a patent, we ■ have that presumption strengthened by the fact that it was) granted after spirited litigation in interferences and after full consideration of the many earlier patents cited against it. The disclosure was revolutionary. The art recovered but one-half of the phosphate. It recognized this wasteful fact. It sought to improve it, but no solution came. To this stationary art the patent disclosed a great step forward. It did away with dump heaps known to contain a vast tonnage of phosphate and did for that art and for those wasteful dumps a major advance which ranked the recovery of the dump heap of phosphate with the salvage of culm banks of the coal art; the use of supposedly worthless slag of iron furnaces; and the supposedly worthless dumps of the gold mining industry. Such economic salvages merit the reward of patent protection. For these and other reasons which the length of this opinion suggests we do not discuss, but all of which we have duly considered, the decree below is affirmed.