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[blocks in formation]

Rubble and riprap

Concrete

Unclassified

Totals

Value

Tons

Value

Tons

Value

Tons

Value

Tons

Value

[blocks in formation]

165,174

3,000
5,961
3,500
14,097
2,000

500
60,000
20,900

$101,506

1,000
4,371
1,500
2,115
3,000

500
33,000
28,517

3,000

$1,500

[blocks in formation]

194,700
93,633

7,425
2,650

301,000
37,453

500
359,650

465
200,833

53,926

360
283,767

53,926

405
128,263

761,394

368,327

6,525

7,060
119,034

2,910
1,765
56,887

38,071

26,228

13,900
38,285

6,950
16,514

40,181
2,000

500

500
5,500
34,310
1,000

10,000

700
500

300
3,850
33,424

500

366

275

336,817

3,000
85,596

3,500
523,223
2,000

500
186,670
217,700
93,633
53,926

860
1,414,336

7,060
211,186
40,285

500

500
5,500
31,676

1,000
16,339
25,181
272,909
481,856
342,000
415,859

45,240
134,324

86,840
142,073

4,522
82,878
7,452
1,000

500
60,529
325,110

500
42,153
4,000
5,105

14,289

$192,110

1,000
46,776

1,500
310,970
3,000

500
98,573
332,167
37,453
53,926

870
700,333

1,765
100,065
17,214

500

300
3,850
33,699

500
5,381

3,581
166,820
242,907
153,900
161,040

44,270
127,520
86,610
85,463

8,500
47,786
6,794

500

250
37,176
92,653

200
27,402
1,500
2,674

4,683

78,091
286,000
79,700

64,465
49,472
128,700
16,425

56,528
12,450

2,050
25,181
103,939

9,864

22,611
1,868

698
3,581
79,396
4,379

316,395

3,351
1,000

131,093
2,386

500

300
381,451
56,000
19,764
41,889
66,808

318
187,188
25,200
13,522
41,884
65,209

10,500
38,098
100,357

10,250
37,898
53,109

[blocks in formation]

+2,422

1,766

51,561
48,742
21,394

8,500
47,697
1,249
500

250
1,000
38,993

200
9,100
1,500

[blocks in formation]

$915,829

996,925

$392,950

1,410,212

$825,679

1,690,619

$905,570

5,718,838

$3,240,028

County

Tons

Alameda
Amador
Butte
Calaveras
Contra Costa
Del Norte
El Dorado
Fresno
Humboldt
Imperial
Kern
Lassen
Los Angeles
Madera
Marin
Mariposa
Mendocino
Modoc
Monterey
Napa
Nevada
Placer
Plumas
Riverside
Sacramento
San Benito
San Bernardino
San Diego
San Francisco
San Luis Obispo-
San Mateo
Santa Barbara
Santa Clara
Santa Cruz
Shasta
Siskiyou
Solano
Sonoma
Trinity
Tulare
Tuolumne
Ventura

*112,142

56,016
48,742
28,656

4,522
82,778
1,595
1,000

500
2,000
101,567

500
14,000
4,000

Totals

1,621,082

Includes chicken grit.

*Includes limestone utilized as asphalt filler.

Total value of production of “Miscellaneous Stone,” by counties, for 1915, compared with 1914, showing increase or decrease in each instance:

County

1914

1915

Increase

Decrease

$381,135

50,895

$76,246

1,300 16,248 1,900 1,000 88,603

250 4,900

308,727

3,250

2,600 237,963

30,553 208,204

$44,258

15,973 127,088 40,095 59,319 5,000

95 68,700

775 953,434 192,764 490,137 15,366

560

70,492 388,609

1,848
940
300

Alameda
Amador
Butte
Calaveras
Colusa
Contra Costa
Del Norte
El Dorado
Fresno
Glenn
Humboldt
Imperial
Kern
Lake
Lassen
Los Angeles
Madera
Marin
Mariposa
Mendocino
Modoc
Monterey
Napa
Nevada
Orange
Placer
Plumas
Riverside
Sacramento
San Benito
San Bernardino
San Diego
San Francisco
San Joaquin
San Luis Obispo.
San Mateo
Santa Barbara
Santa Clara
Santa Cruz
Shasta
Siskiyou
Solano
Sonoma
Stanislaus
Tehama
Trinity
Tulare
Tuolumne
Ventura
Yolo
Yuba

$457,381

1,300 67,143 1,900

1,000 397,330

3,500

7,500 193,705

46,526 335,292 40,095 59,319 5,000

870 1,022,134

122,272
101,528
17,214
1,500

300
32,799
108,387

500 9,027 98,187

5,431 213,440 284,1271 155,000 178,528 163,723 128,270 21,620 99,475 93,391 13,900 98,342 6,794 1,418 4,630 37,576 177,917 2,250

750

900 36,851 1,900 2,674

1,200 149,292

39,202 130,316

2,108 88,315 203,593

1,879 206,802 253,235 110,630 131,978 210,250 119,889 19,440

[blocks in formation]

34,648
15,300
39,093
4,276

125
5,371
71,288
276,516

3,096

59,249
2,518
1,293

741 33,712 98,599

846

1,750

750

900 35,101 1,900 2,674

1,200 134,397

14,895

$4,860,358

$5,011,108

Totals Net increase

$150,750

CHAPTER FIVE.

INDUSTRIAL MATERIALS.

The following mineral substances have been arbitrarily arranged under the general heading of “Industrial Materials," as distinguished from those which have a clearly defined classification, such as metals, salines, structural materials, etc.

These materials, many of which are mineral earths, are produced on a comparatively small scale at the present time. Almost without exception the possibilities of development along these lines are practically unlimited; and with increasing transportation, and other facilities, together with a steadily growing demand, the future for this branch of the mineral industry in California is certainly promising. There is scarcely a county in the state but might contribute to the output.

To date, production has been in the majority of instances dependent upon more or less of a strictly local market, and the following data will show the results of such a condition, not only in the widely varying amounts of a certain material produced from year to year, but in widely varying prices of the same material, often, in different sections of the state. Furthermore, the quality of this general class of material will be found to fluctuate, even in the same deposit, especially as regards price. The war in Europe has affected some of these items, but not to the striking degree that it has the metal markets.

The following summary shows the value of the industrial materials produced in California during the years 1914–1915, with increase or decrease in each instance:

[blocks in formation]

ASBESTOS. Bibliography: State Mineralogist Reports XII, XIII. Bulletin 38. Though asbestos of various grades is known to exist widely distributed in California, the production for the year 1915 was 143 tons, valued at $2,860, the combined result of several small shipments from a number of localities, including Placer, Calaveras, Alameda, and Contra Costa counties. One firm has established a grinding and fiberizing plant in Oakland, and is now manufacturing a series of products in which both asbestos and magnesite play a part. These include steam pipe covering, composition flooring, and plaster for stucco work. The outlook is for a decided increase in the output of these materials during the coming year.

The real history of the development and use of asbestos dates back only about sixty years. Since that time the investigation as to its occurrence, uses, and methods of treatment has been continuous, and its application to everyday life has grown with wonderful rapidity. The first mill built to handle the crude ore and extract the fibre on a large scale by machinery was constructed in 1888.

The first production of asbestos in California was in 1887, when 30 tons were mined, having a crude value of $60 per ton, according to the State Mining Bureau reports.

The bulk of the world's supply of this mineral today comes from Canada; and Canadian asbestos, so far, leads in quality as well as in quantity.

Classification and Characteristics.

The word “asbestos” (derived from the Greek meaning incombustible) as used here includes several minerals, from a strictly mineralogical standpoint. There are two main divisions, however; amphibole and chrysotile. The fibrous varieties of several of the amphiboles (silicates chiefly of lime, magnesia and iron), notably tremolite and actinolite, are called asbestos. Their fibres usually lie parallel to the fissures containing them. Amphibole asbestos possesses high refractory properties, but lacks strength of fibre, and is applicable principally for covering steam pipes and boilers. Chrysotile, a hydrous silicate of magnesia, is a fibrous form of serpentine, and often of silky fineness. Its fibres are formed at right angles to the direction of the fissures containing them. Chrysotile fibres, though short, have considerable strength and elasticity, and may be spun into threads and woven into cloth.

To bring the highest market price asbestos must needs have a combination of properties, i. e., length and fineness of fibre, tensile strength and flexibility—all combined with infusibility. Of these qualities the

most important are toughness and infusibility, and determination of the same can only be made by practical tests or in the laboratory. Given several specimens of the same tensile strength and degree of infusibility, the one having the longest fibre will, of course, be of the greatest value. It must be kept in mind, however, that length of fibre alone, the characteristic which most naturally appeals to the eye, is not the final test in regard to the commercial value of the find; and much short fibre asbestos, which on first appearance is of inferior grade, is being sold and profitably handled at the present time.

The largest Canadian asbestos deposits are worked as open quarries where the ore is roughly sorted before being sent to the mill to be dressed for the market. This method has been found to be cheaper and more satisfactory in every way.

The milling of asbestos ore, while more or less complicated in actual practice, is easy to understand and has one well-defined object in view : That is, the complete eradication of all foreign rock ingredients and the thorough cleaning and separation of the fibres.

Asbestos, roughly speaking, is worth from $20 to $200 per ton. The poorer grades which are unsuitable for weaving, and which, of course, command the lower prices, are used in the manufacture of steam packing, furnace linings, asbestos brick, wall plasters, paints, tilings, asbestos board, shingles, insulating material, etc. The better grades are utilized in the manufacture of tapestries of various kinds, fireproof theater curtains, cloth, rope, etc.

A very important development of the asbestos industry is the rapidly increasing demand for the lower grade material, on account of the numerous diversified uses to which asbestos products are being put, in almost every branch of manufacture. This fact means that many deposits of asbestes will become commercially important even though the grade of the material is far from the best.

It has been discovered only recently that not only does an asbestos wall plaster render the wall so covered impervious to heat, but that in rooms which have given forth an undesirable echo this evil has been absolutely removed. Asbestos pulp mixed with cement and magnesite has been experimented with in the East; and roofing, flooring, and other building material of the most satisfactory sort has been manufactured therefrom. Value and Production.

The value of the domestic production of asbestos has averaged around $43,000 annually, the past ten years, except 1911, which was approximately $120,000. The imports, largely from Canada, for 1915 amounted to $1,407,758, according to U. S. G. S. Mineral Resources, 1915. This value is for crude material; adding the imported manufactured asbestos articles the figure amounts to $1,776,102.

5—25437

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