Various indices, notably rock quality designation (RQD), weighted joint density (WJD), and block quality designation (BQD) have been introduced by researchers to survey joints in boreholes, each with its own advantages and disadvantages. The idea of combining WJD and BQD to use positive features of both formed the main goal of the current study, leading to the definition of an improved BQD . After joint surveys of cores drilled in Kulikosh Marble Quarry, Iran, linear regressions validated by statistical tests showed that BQD is less dependent on the drilling direction than the RQD. An empirical equation was also obtained as , with the help of which one can estimate the value of by measuring the original BQD . Taking into account the joint orientations, is logically closer to reality whereby mining engineers can assess block productivity of stone quarries more accurately.
AladeS, MurianaO, OlayinkaH.2012. Modified volumetric joint count to check for suitability of granite outcrops for dimension stone production. J Eng Sci Techn. 7: 646 – 660.
2.
AraghiMS, SamaniFB, GoudarziMT.2006. A proposal for the modification of RQD (MRQD). In Rock Mechanics in Underground Construction: ISRM International Symposium 2006: 4th Asian Rock Mechanics Symposium, 8–10 November 2006, Singapore, World Scientific; p. 269.
3.
ASTM C119. 2014. Terminology relating to dimension stone. West Conshohocken, PA: ASTM International.
4.
ASTM C503. 2015. Specification for marble dimension stone. West Conshohocken, PA: ASTM International.
5.
AzimianA.2016. A new method for improving the RQD determination of rock core in borehole. Rock Mech Rock Eng. 49: 1559 – 1566.
6.
BakhtavarE, AbdollahisharifJ, LotfiE, OraeeK.2012. Assessment of parameters influence the extraction method selection for the dimension stone quarries. SME Annual Meeting: mine to Market, Now it's Global; Society for mining. Metall Explor. 244 – 248.
7.
BieniawskiZT.1989. Engineering rock mass classifications: a complete manual for engineers and geologists in mining, civil, and petroleum engineering. Wiley. p. 251.
8.
CarvalhoJF, HenriquesP, FaléP, LuísG.2008. Decision criteria for the exploration of ornamental-stone deposits: application to the marbles of the Portuguese Estremoz Anticline. Int J Rock Mech Min Sci. 45: 1306 – 1319.
9.
ChoiS, ParkH.2004. Variation of rock quality designation (RQD) with scanline orientation and length: a case study in Korea. Int J Rock Mech Min Sci. 41: 207 – 221.
10.
DeereD.1963. Technical description of rock cores for engineering purposes. Rock Mech Eng Geol. 1 (1): 18 – 22.
11.
ElciH.2011. Engineerıng geology of Karaburun peninsula limestone. School of Natural and applied Sciences [PhD thesis] Turkey: Dokuz Eylul University.
12.
ElciH, TurkN.2014. Rock mass block quality designation for marble production. Int J Rock Mech Min Sci. 69: 26 – 30.
13.
HaftaniM, ChehrehHA, MehinradA, BinazadehK.2016. Practical investigations on use of weighted joint density to decrease the limitations of RQD measurements. Rock Mech Rock Eng. 49: 1551 – 1558.
14.
HarrisonJ.1999. Selection of the threshold value in RQD assessments. Int J Rock Mech Min Sci. 36: 673 – 685.
15.
HazrathosseiniA, MahdevariS.2018. Applicability quality assessment of dimension stones for service in the buildings (a new approach using a mathematical model and fuzzy logic). J Build Eng. 20: 585 – 594.
16.
HazrathosseiniA, MahdevariS.2019. Geometric quality assessment of in situ blocks in dimension stone quarries. Bull Eng Geol Environ. 78: 2377 – 2385.
17.
HeMM, LiN, YaoXC, ChenYS.2020. A new method for prediction of rock quality designation in borehole using energy of rotary drilling. Rock Mech Rock Eng. 1 – 12. DOI: 10.1007/s00603-020-02091-6.
18.
HudsonJ, PriestS.1983. Discontinuity frequency in rock masses. Int J Rock Mech Min Sci Geomech Abstr. 20: 73 – 89.
19.
LiL, OuelletS, AubertinM.2009. An improved definition of rock quality designation, RQDc. Proceedings of the 3rd Canada–US Rock Mechanics Symposium & 20th Canadian Rock Mechanics Symposium RockEng09 Rock Engineering in Difficult Conditions, Toronto, Ont; p. 9–15.
20.
MilneD, HadjigeorgiouJ, PakalnisR.1998. Rock mass characterization for underground hard rock mines. Tunnelling Underground Space Technol. 13: 383 – 392.
21.
PalmstromA.1982. The volumetric joint count―a useful and simple measure of the degree of rock mass jointing. Int Assoc Eng Geol Int Congress. 4: 221 – 228.
22.
PalmstromA.1995. RMI–a rock mass characterization system for rock engineering purposes [Ph. D. Thesis] Oslo, Norway: Department of Geology, University of Oslo.
23.
PalmströmA.1996. The weighted joint density method leads to improved characterization of jointing. International Conference on Recent Advances in Tunnelling Technology ; New Delhi, India. p. 1 – 6.
24.
PalmstromA.2005. Measurements of and correlations between block size and rock quality designation (RQD). Tunnelling Underground Space Technol. 20: 362 – 377.
25.
Sazehkav Co. 2019. Report of explorational studies in Dehbid region. Shahrood, Iran: Shahrood University of Technology.
SonmezH, NefesliogluH, GokceogluC.2004. Determination of wJd on rock exposures including wide spaced joints. Rock Mech Rock Eng. 37: 403 – 413.
28.
SousaLM.2007. Granite fracture index to check suitability of granite outcrops for quarrying. Eng Geol. 92: 146 – 159.
29.
TaboadaJ, VaamondeA, SaavedraA.1999. Evaluation of the quality of a granite quarry. Eng Geol. 53: 1 – 11.
30.
TerzaghiRD.1965. Sources of error in joint surveys. Geotechnique. 15: 287 – 304.
31.
YarahmadiR, BagherpourR, SousaLM, TaherianS-G.2015. How to determine the appropriate methods to identify the geometry of in situ rock blocks in dimension stones. Environm Earth Sci. 74: 6779 – 6790.
32.
ZhengJ, YangX, LüQ, ZhaoY, DengJ, DingZ.2018. A new perspective for the directivity of rock quality designation (RQD) and an anisotropy index of jointing degree for rock masses. Eng Geol. 240: 81 – 94.
. After joint surveys of cores drilled in Kulikosh Marble Quarry, Iran, linear regressions validated by statistical tests showed that BQD is less dependent on the drilling direction than the RQD. An empirical equation was also obtained as 
, with the help of which one can estimate the value of 
by measuring the original BQD 
. Taking into account the joint orientations, 
is logically closer to reality whereby mining engineers can assess block productivity of stone quarries more accurately.