14 DEPARTMENT BULLETIN 1216, U. S. DEPT. OF AGRICULTURE 
piles or bins. It is recommended, in order that the sample may be representa- 
tive, that separate samples be taken at different times while the material is 
being loaded. If the sample has to be taken from the bin or stock pile, several 
samples shall be taken from different parts of the stock pile and from the top of 
the bin and the loading chute. These separate samples shall be well mixed in a 
composite sample and the sample for test obtained by the quartering: method. 
7. (O) Where it is not practical to visit the plant, samples for both quality 
and size shall be taken from different parts; of the car or boat during unloading. 
It is recommended that separate samples be taken from the top. middle, and 
bottom of car or boat. These separate samples shall be well mixed in a com- 
posite sample and the sample for test obtained by the quartering method. The 
results of tests on crushed stone for quality are not considered comparable with 
results from samples specially broken for test in the laboratory, but the general 
quality of the stone can be ascertained and check tests on various shipments 
should indicate any change in quality. In this case, tests for both quality and 
size can be made on the same sample. 
(&) Where test is to be made for size only, it is recommended that a small 
set of screens and a pair of scales or some unit measure receptacle for measuring 
volume be used for field testing in order not to delay decision on the use of the 
material. Occasional check tests can be obtained from the laboratory to assure 
a fair degree of accuracy in field testing. 
8. (a) The sample of crushed stone for mechanical analysis shall weigh at 
least 50 times the weight of the largest piece therein. 
(&) The sample for concrete test will depend on the kind of tests to be made 
and the number of specimens necessary. 
C. SAMPLING OF FIELD STONE AND BOWLDERS 
9. A detailed inspection of the deposits of field stone and bowlders, over the 
area where the supply is to be obtained, shall be made. The different kinds of 
stone and its state of preservation in the various deposits shall be recorded. 
10. Separate samples shall be taken of all stone of different classes that a 
visual inspection indicates ; from state of preservation and degrees of lamina- 
tion, would be considered for use in construction. 
11. Records accompanying samples of field stone and boAvlders, in addition to 
general information, shall contain the following: 
(a) Location of supply. 
The plotting of the field, stone, and bowlder area on a United States topographic 
or a similar map is recommended for this purpose. 
(&) Approximate quantity available. 
A fairly accurate estimate Of amount of stone in fences can be made by 
measuring a cross section and pacing the length. It is more difficult to esti- 
mate the amount of stone scattered on the ground and ordinarily such deposits 
do not pay to work unless quite congested. 
(o) Information regarding the percentage of different classes of stone which 
were sampled and the percentages of material wdiich can be rejected by visual 
examination and may have to be handled and spoiled. 
This information regarding the percentages of different kinds of material 
can only be estimated and the degree of accuracy attained will depend almost 
entirely upon the experience and skill of the individual. 
SAMPLING OF BLAST-FURNACE SLAG 
12. It is recommended that blast-furnace slag be sampled for size and quality 
by the method specified for broken stone. 
SAMPLING OF SAND AND GRAVEL 
A. NONCOMMERCIAL DEPOSITS 
13. Noncommercial as used here includes all undeveloped sand and gravel 
deposits and all developed deposits where the material is not washed or 
screened. 
14. (a) The investigator should realize that few, if any, natural sand and 
gravel deposits are uniform, and when a sample is taken the quantity of ma- 
terial in the deposit similar to the sample shall be ascertained as nearly as 
possible. 
