Modeling and simulation of crushing process of spiral mining head

Vol.13 No. 2J. CENT. SOUTH UNIV. TECHNOL.Apr. 2006Article ID: 1005 - 9784(2006)02 -0171 -04Modeling and simulation of crushing process of spiral mining head°XIA Yi-rmin(夏毅敏)', BU Ying-yong(卜英勇)', TANG Pu-hua(唐蒲华)*，ZHOU Zhi-jin(周知进)，MA Zhi-guo(马治国)'(1. School of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China;2. Department of Mechanical and Electrical Engineering, Changsha University, Changsha 410003, China;3. School of Mechanical and Electrical Engineering, Hunan University of Science and Technology,Xiangtan 411201, China)Abstract: According to the characteristics of spiral mining head for deep seabed cobalt-rich crust, the kinematicmodel, cutting loads model, quantity of cutting picks model of mining head, granularity distribution model and ener-gy consumption model were constructed. Based on these models, computer simulation program of cutting loads wasdeveloped with VB software. The mechanical parameters of mining head were obtained in the cutting depth range of5- 160 mm. Making use of the simulation results, the effect of cutting depth of spiral mining head on the miningprocess was studied. The results show that the maximum force of single pick is 4. 705 1 kN, the maximum force andtorque of spiral drum of mining head are respectively 34. 166 8 kN and 3. 8795kN. m at the cutting depth of160 mm.Key words: spiral mining head; modeling; simulation; cutting depthCLC number: TD424; TP391.9Document code: A1 INTRODUCTIONto construct pertinent model of crushing cobaltcrust with mining head and to investigate the influ-The research of mining deep seabed cobalt-richence of cutting depth on crushing process. Liu etcrust is a hotspot of international oceanology'l. .al1-3]3 have done some researches on this subject.Based on the mining manganese nodule, lots of re-In this paper, crushing process of spiral miningsearches on mining cobalt crust have been madehead was modeled and simulated.deeply and many kinds of methods, such as the im-proved CLB, mining vehicle 十lifting system十2’MODELS OF CRUSHING PROCESS BY SPIRALsurface supporting ship have been put forward.MINING HEADMining vehicle consists of collecting machine ，tracked treading machine and spiral miningheadLz.3]. The first step of mining cobalt crust is toIn order to study the working characteristicscrush and peel off cobalt crust with mining head.of mining head, the kinematic model, cutting loadsThe main factors which determine collecting ratiomodel, quantity of cutting picks model of miningof cobalt crust, interfusing ratio of mullock, ener-head, granularity distribution model and energygy consumption, crushing granularity and workingconsumption model were constructed.stability of mining vehicle are structural parame-ters of mining head ( quantities of helical line and2.1 Kinematic model of mining headpicks, shape and arrangement of picks), workingIt is assumed that the mining head goes for-parameters ( cutting depth, rotational speed of roll-ward at a constant speed Uq in the horizontal direc-er, feed speed), physical and mechanical character-tion ( direction x), and moves at a constant speedistics of cobalt crust and base rock[4-]. Because thestructural parameters of mining head and perfor-vp in the vertical direction (direction z) when it ismance of base rock cannot be changed, it is the on-needed. The mining head rotates at the speed of nly way to adjust three working parameters to makearound its axis and speed of n' around another axismining vehicle work effectively in optimal state,on yoz plane. So the trace of random point in theespecially the cutting depth[8-10]. So it is necessary中国煤化工D Foundation tem: Proiee(DY105 - 03 -02 -1) supprted by the Deep OcearJMHCNMH G_e(50474052) sppredeby the National Natural Science Foundation of ChinaReeved date: 2005 -06 -25; Accepted date: 2005 -08-16Correspondence:XIA Yi-min, PhD candidate; Tel; + 86-731-8830245; E-mail: xiaymj@mail. csu. edu. cn●172●Journal CSUT Vol. 13 No.2 2006(xi = Vqtevery tooth is varied with time. According to theJin = B,cosβmovement rule of mining head and model of recon-zn = Upl' + B,sinβ.(1)structed numerical terrain, real time cutting depth(A = 2πn't"of mining head can be obtained.where β is the angle between the rotational axisWhen the cutting depth H, < <60 mm, the cut-and xoy plane, B; is the distance from point i toting loads of single pick in axial, radial and tangentthe right of spiral drum，t is the random timedirections(Fu，Fn， F.) are respectively as fol-point, t' is the control time to change the cuttinglows:depth, t'∈t, l"∈t, t" is the control time to very(Fu =士F(万++)气angle of the rotational axis.Fm = K.F。+ 100k,oSsThe trace of tip of random pick isF. = 10A0.35b+0.3Clkikaksh, + 100fk,oSa(工n = R.c(台;)+ R.cs(k +2nm )+uib+ Bh:(5)yi = So+il(1一cosβ)cotβ .where A and σ are the cutting impedance and in-zn = R,sin((点)+ Rsi(ip; +2mt)+.r-tensity of pressure of cobalt- rich crust, respective-ly, l is the distance between two picks, ki, kz, ks,ilcot Psinβk, and K, are the coefficients which have relation to(B. = 2rn't"cutting conditions, f is the coefficient of cutting(2)resistance, Sa is the attrited area, and e, c and dwhere i=0, 1,."，15, stand for the coordinatesare the empirical coefficients.of cutting pick on the first helical line, R, is theWhen the cutting depth H.≥60 mm, formuladistance between rotational axis and tip of pick, S。(4) will not be changed. But it is assumed that theis the distance from cutting pick 0 to ragged edge, .tooth begins to cut the bedrock, the total force isl is the distance of neighbor pick on the same heli-composed of two parts. The numerical values of Acal line, β is the spiral angle.and σ are replaced by those of the bedrocks to cal-culate the part force at H>60 mm。(工n = R,cos[(i- 15)]+2.3 Cutting loads model and energy consumptionR,cos[言(i- 15) + 2πnt 1+ v。tmodel of spiral mining headInstantaneous pull force F, side force F, andyn = So+S+(i- 15)l(1 - cos β)cotβ(3)feed force F, of mining head are respectively as fol-Za = R,sin[[(i一15)]+Rsin[R (i- 15) + 2πnt 1+[Fx =(Fsing., - Fwcos q,)vpl'一(i- 15)lcot PsinβF, =- 2(Fncosq.+ Fmsinq,) (6)[风= 2rn't"where i=16, 17，"，31, stand for the coordi-nates of cutting pick on the second helical line, S isthe distance between two helical lines.The torque of mining head is(7)2.2 Model of cutting loads of single pickT.=n2P。Because the thickness of cutting scrap ha iswhere P: is the angle between the pick and xoydifficult to be directly controlled during the actualplane, k is the total quantity of picks of miningmining process, it is controlled with the cuttinghead, and r; is the working radius of the pick.The energy consumption of mining head is asdepth H. The relationship between hu and H, canfollows:be expressed as follows:P= T,2πn8)hn=_v,(0. 95√2R,H.E H+0.05R,)(4)中国煤化工2RnBecause the terrain is random at seabed, as toHCNMH(nportant influenceruma given terrain (usually the length is 300 mm), theon working life of mining vehicle, mining head andheight of mining head is kept invariable in order toick. In order to evaluate the cutting stability ofkeep the best mining ratio. The cutting depth ofmining head ( undulation of load)， the coefficientXIA Yi-min, et al, Modeling and simulation of crushing process of spiral mining head173●of undulation δ, is used to express the undulationcomputer simulation results are validated by exper-extent of cutting load. Its calculating formula isiments.(w,- w;)"dp3.2 Simulation resultsδ;=12When the cutting depth is in the range owhere W, is the cutting load of every sampling5- 160 mm，the relation chart between force ,torque, undulation coefficient and cutting depthpoint, and W; is the average load.can be obtained. The results are shown inFigs.1-3, where Fmox stands for the maximum2.5 Quantity of cutting picks in cutting districtforce of single cutting pick, F,ax, Fs.w and Fs.minThe load characteristic of mining head is relat-stand for the maxinum force, average force anded to the quantity of picks which are cut at theminimum force of spiral drum, respectively, Tx，same time. As to the adopted mining head withTv and Tmn stand for the maximum, average anddouble helical line, the angle between two picks inone helical line is 21.8°. The calculating formula of4(quantity of cutting picks at the same time is as fol-3530lows:H= R[1 - cos(mB)]，2:where βis 21.8* , m is the number of cutting pickE 20in the cutting district, R is the average distance be-15tween rotational axis and tip of pick.10According to formula (10)， we can concludethat only 2 picks are cut when the cut depth is less20406080100120140160than 12. 2 mm, and 4 picks are cut at the sameH/mmtime when the cutting depth is from 12. 2 mm toFig. 1 Relation between force and cutting depth47.2 mm, and 6 picks are cut at the same time1- Fe.ou; 2-Faw; 3一Fx; 4-Fo.minwhen the cutting depth is from 47.2 mm to 99. 8mm, and 8 picks are cut at the same time when the4.0pcutting depth is from 99. 8 mm to 162. 6 mm.3.5-3.02.6 Granularity distribution modelE 2.51The broken cobalt and bedrock have good2.0-fractal structure, and its distribution law can be1.5-described with fractal dimension. The fractal di-1.mension D can be obtained by means of the mass0.5cumulative function below sieve as follows.F(x)="'(x(11)0406080100120140160mrwhere m'(x) and mτ are the cumulated mass be-Fig. 2 Relation between torque and cutting depthlow sieve and total mass, respectively, x and xmxare characteristic dimension of mesh and maximum.0-dimension, respectively..9t3 EFFECT OF CUTING DEPTH ON CUTTING :0.8-CHARACTERISTICS OF MINING HEAD0.7-0.6- '3.1 Computer simulation of cutting load of mining0.4-According to the constructed models of crush-ing cobalt crust, a program is accomplished withVB software to simulate the crushing process of中国煤化工120 140 160mining head.After the expected parameters are input, theCNMHGFig.s relauon Detween unaulation coefficientcurve of time field, spectrum chart and numericaland cutting depthoutput result of pertinent force, torque and undu-1-8p; 2--- -δ .lation of load can be obtained. And parts c●174●Journal CSUT Vol.13 No.2 2006minimum torque of spiral drum, respevtively, andVB software and validated by experiments.δτ and δp stand for the undulation coefficients of3) The influence of different cutting depths onthe drum's torque and force, respectively.mining process is studied. The key mechanical pa-From Figs. 1 - 3, the following conclusionsrameters are obtained. The maximum force of sin-can be obtained.gle pick Fmx is 4. 705 1 kN; the maximum force of1) The maximum force of single pick Fmax isspiral drum Fd,max is 34. 166 8 kN; the maximum4.705 1 kN; the maximum force of spiral drumtorque of spiral drum Tx is 3. 8795 kN●m. AndFd,max is 34.166 8 kN; the maximum torque of spi-the potential modality of power is put forward.ral drum Tmx is3.8795kN. m.2) With the increase of cutting depth, the cut-REERENCESting force of single pick increases nonlinearly from1] Glasby G P. Deep seabed mining: past failures and fu-1. 4210 kN at cutting depth of 5 mm to 4. 7050 kNture prospects[J]. Marine Georesources and Geotech-at cutting depth of 160 mm.nology, 2002, 20(2): 161 - 176.3) The total force and torque of mining head[2] LIANG Ping, SHI Hai-lin, CUI Bo. Mining methodsIso increase with the increase of cutting depth,of seabed cobalt-rich crust[J]. Metal Mine, 2002, 33and they vary greatly at different cutting depths. If(3): 114- 117. (in Chinese)the cutting depth is small, the force and torque in-[3] LUO Chun-lei, HU Jun-ping, LIU Wei. Device andcrease equably. If the cutting depth is greater thanf mining cobalt crust[J]. Journal of Central20 mm，especially over 40 mm，the force andSouth University of Technology: Natural Science,torque increase greatly. The force is 4. 088 5 kN2002, 33(6): 617 - 620. (in Chinese)and the torque is 651.3N●m at cutting depth of[4] Tetsuo Y, Chung J S, Katsuya T. Geotechnical pa-rameters and distribution characteristics of the cobalt-40 mm. But when the cutting depth increases up torich manganese crust for the miner design[J]. Interna-160 mm (4 times), the force increases up totional Journal of Offshore and Polar Engineering,34.166 8 kN (8. 36 times) and torque increases up1995, 5(1): 75 - 79.to3.879 5 kN●m (5. 96 times). The reason for[5] BU Ying-yong, LIU Yong. Computer simulation andthis is that quantity of cutting picks at one time in-analysis of the load chart of drum-type collecting headcreases from 2 to 8.of deep-sea cobalt crust excavating robot[J]. Journal4) When the cutting depth is less than 12 mm,of Central South University of Technology: NaturalScience, 2002, 33(3); 289 - 292. (in Chinese)the minimum cutting force and torque of drum is zero.[6] Krauze K, Paraszczak J. Performance of helical cuttingThe reason for this is that only 2 picks are cut whendrum with additional picks on the face side[J]. Miningthe cutting depth is less than 12 mm. When the formerScience and Technology, 1990, 10(1): 93 - 96.pick is out of cutting, the next pick is not cut. So the[7] Larson D A, Tandanand s, Boucher M L. Physicalforce and torque of drum equal zero in a very shortproperties and mechanical cutting characteristics of co-ime.balt-rich manganese crusts[R]. Minneapolis: Bureau5) With the increase of cutting depth, the un-of Mines, US, 1987.dulation coefficients of force and torque decrease[8] QIN Xuan-yuan, BU Ying-yong. Study on multilevelfirst (at cutting depth of 12- 16 mm) and then in-model of optimized cut. depth inreal-timemining ofocean cobalt-rich crusts[J]. The Ocean Engineering,crease. When the cutting depth is from 5 mm to2005, 23(3): 99- 104. (in Chinese)12 mm, the undulation coefficient decreases sharp-[9] YAO Bao-heng, LI Guir xuan, DING Fei. Caleulationly. The reason is that the quantity of cutting picksand influence factor analysis on coal cutting force ofat one time increases with the increase of cuttingpick[J]. Coal Science and Technology, 2002, 30(3):depth. When the cutting depth is in the range of35 - 37. (in Chinese)12 - 16 mm, the undulation coefficient is the mini-[10] JIANG Nian-zhao, HU Ying-xi, CHEN Qi-mei, Themum because the cutting angles of picks of mininganalyses and study of instantaneous load about helixhead almost keep constant.drum[J]. Coal, 2000(1): 22 - 24. (in Chinese)6) According to working speed of mining vehi-[11] LIU Yong. Theoretic and experimental research ofcle and obtained force and torque, powers neededmethod for applying twistroller to cut and collectdeep-sea cobalt crust[D]. Changsha: School of Me-at different cutting depths are very different. So inchanical and Electrical Engineering, Central Southorder to decrease the ratio of energy consumptionUniversity, 2002. (in Chinese)of mining vehicle, double pump should be adopted[12] TANG Purhua. The study on dynamic characteristie ofin the hydraulic system.spiral mining head for deep seabed cobalt crust [D].Changsha; School of Mechanical and Electrical Engi4 CONCLUSIONS[13]中国煤化工，200 (in Cinmse! modeling of optinized1) Kinematic model, cutting loads model andrsea-cobalt-rich crustsquantity of cutting picks model of mining head areYHCNMHrrain[D]. Changsha:constructed for cutting and crushing cobalt.School of Mechanical and Electrical Engineering, Central2) According to the constructed models, sim-South University, 2005. (in Chinese)ulation program for cutting load is developed with(Edited by CHEN Wei-ping)