22. The method of using a riffle divider shall be as follows–
(a)the riffle divider shall be placed on a firm level surface;
(b)the riffle divider and pans shall be clean;
an empty pan shall be placed on each side of the riffle divider to receive the discharge from the chutes;
(d)the entire composite sample shall be poured evenly into the other pan(s);
(e)the seed shall then be poured from the pan(s) evenly along the entire length of the hopper;
(f)the two pans into which the seed has passed shall then be replaced with empty pans;
(g)the procedures specified in sub paragraphs (e) and (f) shall then be repeated twice to mix the sample thoroughly;
before reduction, the composite sample shall have been thoroughly mixed using the procedures specified in sub paragraphs (c) to (g). The contents of one of the two receiving pans shall then be set aside. If the seed and any other particles in the second pan is of at least the minimum weight prescribed in paragraph 26 of Part II of this Schedule for a sample, it may be used as a submitted sample. If the weight of seed in the second pan is greater than the minimum weight prescribed in paragraph 26 of Part II of this Schedule for a sample, it may be reduced using the procedures specified in sub paragraphs (i) to (k);
(i)an empty pan shall be placed on each side of the divider to receive the discharge from the chutes;
(j)the contents of the second pan shall be poured evenly along the entire length of the hopper;
(k)the contents of one of the two pans into which the seed and other particles have passed shall then be set aside. If the weight of seed and other particles in the other pan is still greater than the minimum weight prescribed in paragraph 26 of Part II of this Schedule for a sample, it may be used as a submitted sample intact or it may be reduced further using the procedures specified in sub paragraphs (i) to (k);
(l)if the weight of seed and other particles in either of the two pans set aside in the procedures specified either in sub-paragraph (h) or sub paragraph (k) is less than the minimum weight prescribed in paragraph 26 of Part II of this Schedule for a sample, the procedures specified in sub paragraphs (m) to (q) shall be used;
(m)an empty pan shall be placed on each side of the divider to receive the discharge from the chutes;
(n)the contents of one of the pans shall be set aside. The contents of the other pan shall be poured evenly along the entire length of the hopper;
(o)one receiving pan and its contents shall then be removed and replaced with an empty pan. The other pan, with its contents, shall be left in place;
(p)the contents of the pan removed during the procedure specified in sub paragraph (o) shall be poured evenly along the entire length of the hopper so that two sub-samples of different weights shall be produced;
(q)the procedures specified in sub paragraphs (o) and (p), when repeated, constitute the process of continuous halving, and shall be repeated using whichever sub-sample is appropriate until sufficient seed and any other particles is obtained in one pan, which, when added to the seed and any other particles set aside during the procedure specified in sub paragraph (n), produces a submitted sample;
when two submitted samples are required from one composite sample, one composite sample of at least twice the minimum weight prescribed in paragraph 26 of Part II of this Schedule for a sample shall be obtained using the procedures specified in sub paragraphs (c) to (g) and (h) to (q), as appropriate. The composite sample shall then be divided into two parts by passing it once through the riffle divider; and
(s)when three submitted samples are required from one composite sample, one composite sample of at least three times the minimum weight prescribed in paragraph 26 of Part II of this Schedule for a sample shall be obtained using the procedures specified in sub-paragraphs (c) to (g) and (h) to (q) as appropriate. A submitted sample shall then be extracted using the procedures specified in sub paragraphs (c) to (g) and (h) to (q), as appropriate. All portions of seed which have been set aside shall then be recombined and two submitted samples shall be obtained from this residue of the composite sample by following the procedure specified in sub paragraph (r).
Commencement Information
I1Sch. 5 para. 22 in force at 1.7.2005, see reg. 1(1)