THE CHEMICAL NEWS,

VOL. CXXV., No. 3262

MINERALS DEPOSITED BY BACTERIA IN MINE WATER. OBSERVATIONS IN THE KIMBERLEY DIAMOND MINES.

At a meeting of the "Diamond Fields' Mining Institute," held in Kimberley on July 7th, 1922, with Mr. A. F. Williams, General Manager of De Beers Consolidated Mines, in the chair, Mr. John Parry, the Company's Chief Chemist, described some abnormal mineral deposits found in the De Beers Mine.

In November, 1917, several specimens of very unfamiliar looking minerals were handed into the Laboratory for analysis and report.

Although work had been carried on in this mine for at least 30 years prior to this date, nothing of a similar nature seems to have been observed before. Indeed, it was not until haulage operations had been discontinued for nearly ten years, viz., since 1908, that their presence had been noted at all.

In the Kimberley Mine, where mining operations had been curtailed for a briefer period than this, a few small specimens, identical in character and composition to some of those from the De Beers Mine, have been obtained from a small cavity in the walls of the shaft.

In all the other mines, where work has been maintained uninterruptedly, no such minerals have been known to occur.

It is important, to note that all these minerals were found either in the shaft itself, or on the floor of certain levels closely adjacent to the shaft.

A very cursory inspection served to convince anyone familiar with the ordinary minerals found on the numerous working levels of the mine, of the unusual character exhibited by these particular specimens.

The samples chemically examined were as follows:

No. 1.-A long cylindrical piece, which formed only a small portion of a huge deposit, found occupying the entire length of a vertical iron pipe, 180 feet long by 6 inches in diameter, erected in the Prospect Shaft of the mine, starting at the 1860 ft. level and terminating at the 2040 ft. level.

The exterior surface of the cylinder is of an entirely different colour to the mass of the core, being a dirty greyish white, while the mass is of a deep cinnamon brown. This surface, too, is rough and covered with innumerable shallow depressions; while the interior surface is brilliantly black and with peculiar undulatory oval elevations; i.e., of somewhat botryoidal characters.

The photograph (Fig. 1) exhibits the cylindrical outline; and a photograph (Fig. 2) exhibits a good idea of the interior surface with the peculiar undulations.

The cylinder as shown does not represent the full thickness of this pipe core as originally found, for its total diameter is

only 4 inches, while the full diameter of the pipe is 6 inches. Between this coloured portion of the core and the pipe wall was another inch or so of a white deposit. This white portion was rather soft and so loosely adherent that a vigorous tap with a hammer on the pipe easily detached it, and permitted of the ready removal of entire pieces of the solid core. None of this white portion was preserved by the miner who discovered the material. All that remains of it is the dirty white skin just alluded to. This remnant is not particularly soft and adheres pretty firmly to the rest of the core. Sufficient of it, however, was eased off for purposes of analysis.

The whole mass of the material is very brittle, and possesses a peculiar fibrous

appearance.

Sample No. 2: This sample consisted of thin fragments of a scale which I collected ersonally on the 1,760 ft. level. The pieces were removed from the surface of some water lying in a depression on the floor of the tunnel. The whole surface of this water was covered with it as with a sheet of ice. There were many other pools and tunnels on this level, all similarly covered. In some there was a bulging of this surface coating, as though considerable pressure was being exerted beneath; while in others, there was evidence that this pressure had been great enough to fracture this surface skin, and the fractured portions, being of

Fig. 3.

greater sp. gr. than the water, were fourd lying at the bottom of the liquid, and such portions, when taken from the water, could be fitted into the broken surfaces. The thickness of this skin averaged 1 millimetre. It was opaque and of a faint brownish tint, and very brittle.

The pressure alluded to was in all probability due to an accumulation of gas, but at the moment I had no means available for collecting any of it for analysis, and on a subsequent visit I found all the surfaces had been broken.

I was unable to obtain any definite information as to the length of time required for this solid skin to form on these pools, for though the mine had been idle for ten years, it was only when the miner (Mr. Waddington) was placed in charge, about seven months prior to my visit, that any observation was made as to the occurrence of this peculiar deposit. From his remarks I assume that possibly only several months were needed for their formation. Composition of No. 2 Sample.

%

They

Sample No. 3: This sample also occurs as sheets covering pools of water. are of equal thickness to Sample No. 2, but are of a uniform blood-red colour. Heid before a strong light they are semi-transparent and of a homogeneous structure. Fragments measuring 12 x 10 inches were easily procured, and were not so brittle as Sample No. 2, and were strong enough to resist any gas pressure from beneath, as all the specimens met with were perfectly flat. The upper surface was fairly smooth, but here and there on the underside small clusters of minutely globular particles occurred, identical in composition to the sheets. In some places a second sheet had been formed immediately beneath the first in almost optical contact. The insertion of a knife blade, however, between the two sheets caused a clean separation.

These samples were found on the 2,040 ft. level only.

Composition of Sample No. 3.

The fragment illustrated in the photograph (Fig. 3), when first discovered, was as completely enveloped with the foreign material as an egg with its shell. The exposed surface of this, like the sample from the pipe, is brilliantly black, and perfectly smooth and glassy. The underside is only a little less bright than the upper, which is accounted for by its lying in contact with the dirty floor of the tunnel, and is also less smooth, as this surface shows an exact im press of the irregular ridges and depressions. of the floor, as though it had been pressed down on it in a semi-solid condition, like a seal on warm wax. When this black coating was fractured, it was seen (as the photo shows very distinctly) that it consisted of two layers, though curiously enough the surface of the innermost layer was as brilliantly black and glassy as the outer one, and could be easily separated Evidently the deposition of the second coat must have occurred very long after the first.

The nucleus of another one of these samples, from which the black coating had been more completely removed, consisted of a piece of the tunnel rock (? basalt), 6 inches long by 2 inches wide, and varying from 1 to 1 inch thick. It was very irre gular in shape and angular.

The two coats varied in thickness: the lower between 1/16 to of an inch; the upper sometimes reaching of an inch. In spite of the angularity of this stone, the outer surface of the complete specimen was smooth and roughly dome shaped, entirely concealing the irregular shape of the internal fragment of rock.

Quite a large number of such specimens were found on this level (1,920 ft.), all ex

hibiting a similar confluent-surface, and a double coating, and only differing from eahc other in size.

(a) Buses and Acids: Calcium Oxide

Potassium Oxide

In parts per 100,000.

3.08 parts

Magnesium Oxide

1.00

Sodium Oxide

339.60

1.41

2.70

The occurrence of these deposits struck me as so anomalous that I was curious to see for myself the conditions under which they were discovered. Accordingly, accompanied by one of the laboratory assistants (Mr. Falck) and Mr. Waddington (the miner in charge), I descended this De Beers Mine in March, 1918. We descended the Prospect Shaft by cage to the 1,720 ft. level, and continued from that point by upright iron ladders to the 2.040 ft. level, spending some time at various levels the way down. The most interesting of these levels was that at 1,920 feet. The portion of the tunnel immediately adjacent to the shaft was about 9 feet high and 14 feet wide. Here, on the floor, we came across the first samples of the black shiny deposit in the process of formation.

Scattered indiscriminately over the floor were fragments of the tunnel rock and pieces of wood tnd iron; some already completely enveloped in the black coating, others partially so, and again others showing the very initial stage of the deposition. And the source of all this abnormal forma. tion was just water; water as it fell in intermitent drops from various parts of the roof. At first it appeared that this water was percolating through the rock from an upper level, but subsequent examination of the water afforded evidence that this could not be so. It was really derived from water rapidly streaming down the walls of the shaft itself, some of which, on reaching the opening of this level, would be carried along the roof between the innumerable minute ridges by capillary attraction, and fall ultimately and irregularly as drops. Beyond 6 feet from the shaft no drippings at all occurred, though the tunnel was composed of the same kind of rock for many yards further in.

Bottles were placed beneath the more rapidly falling drops, and a gallon of this water collected.

On analysis this water yielded the following data:

Silica

The stone illustrated in the photograph (Fig. 3), and all the samples alluded to in No. 4, were picked up on this level, while the water was still dripping on to them. Here, too, the upper end of the pipe which had contained the core illustrated in Figs. 1 and 2, was exposed. Seven months prior to my visit this opening had been covered over with a plank, and during even that short period the continual dripping of the water had produced on its surface a thin deposit consisting of the same peculiar black material as upon all the other samples.

From this point we descended to the 2,040 ft. level by the iron ladder. Water was trickling down this ladder continuously and all the rungs were completely covered with the black deposit, the lowermost ones being perfectly smooth and extremely slippery. Portions of the coating were chipped off for analysis. At the bottom of the shaft (2,040 feet down), there lay a mass of contorted wire rope, which looked as if it were covered with molten pitch, so bright and black was it from long accumulation of this deposit.

(To be continued.)

The Manchester Section of the Society of Chemical Industry held its first meeting for the session 1922-23 at the Textile Institute, October 6th. Dr. E. Ardern presided, and Dr. E. F. Armstrong, the President of the Society, was also present.

The Section is making a special effort to increase the membership of the Society, and for this purpose each member has been sent, with the annual agreement, a prospectus setting out the advantages of membership of the Society of Chemical Industry and also enclosing the usual form of application for membership. It is further pointed out that now is the most suitable moment for chemists to join the Society, as the year commences in January, when the new Volume of Proceedings and Review

commences.

The Chairman said that the next meeting would be a joint one, between the Manchester Sections of the Society of Chemical Industry, the Society of Dyers and Colourists, the Institute of Chemistry, and the Manchester Literary and Philosophical Society. They were fortunate in having Dr. F. W. Aston, of Cambridge, to come and speak to them about " Isotopes." Professor Bragg, as a representative of the Manchester Literary and Philosophical Society, would preside at the meeting. There was also something in the nature of an innovation to announce. A joint meeting had been arranged between the mernbers of the Manchester Section and the Liverpool Section. This joint meeting would be held in Manchester, and a paver would be read by Dr. Levinstein.

It was hoped that next Session another joint meeting would be held in Liverpool. Reciprocity of that character could not buti be helpful to the general interests of the Society, and also be very advantageous to the members of the two sections. There were now over 600 members in the section, and it was the opinion of the hon. Secretary that that number could be easily increased. No one need be frightened by the fact that the syllabus showed the list of ordinary meetings to be filled. The hon. Secretary would be quite willing, provided the Committee of the Section approved of the papers submitted, to arrange for additional meetings.

The President of the Society, Dr. E. F. Armstrong, F.R.S., then delivered an address, entitled, "PRACTICE AND THEORY IN AN INDUSTRIAL PROBLEM.'

The main object of the few words I shall say to-night is to illustrate to you the extreme breadth of chemical problems, and the necessity for breadth both in the training and in the mind of the chemist if he is to succeed in his profession. The problem I have chosen is one which the force of circumstances has brought me personally closely into touch with, and therefore one which I do happen to know a good deal about. It is also a problem which I think is suitable for demonstration, and the problem is that of fat hardening, or, as it is known, the hydrogenation of fats. Dealing with the matter, in the first place historically, a laboratory investigation carried out by an eminent French savant, led to the discovery that if you pass certain organic substances together with hydrogen over finely divided metals, that reduction of these organic substances took place; that is to say, if they contained an unsaturated linkage that hydrogen was added to these linkages and they became saturated. That sort of fact was well known, or fairly well known, in connection with such metals as platinum and palladium, but it was a definite advance in our theoretical chemistry when nickel was found to have this power. Sabatier, who discovered this, naturally exploited the field as rapidly as he could. Among other things he tested the behaviour of the unsaturated fatty acids and fats towards this new reagent, with very indifferent success.

Then let us pass from the laboratory to that other class of chemist, the great class of people who are always trying to turn the facts which they read in the literature to profitable account. Among others, a certain Dr. Norman saw the bearing of Sabatier's observations on the fat industry. He tried very hard successfully to apply