Shearex VM-60SR excavator mulcher

The head that forces a fleet decision

A 149 cm rotor on the front of a 22 tonne excavator is as much mulcher as the excavator architecture sensibly carries. That is why the VM-60SR, alone in the Shearex VM excavator mulcher range, should be bought only after the buyer has honestly modelled the alternative: a purpose-built mulching carrier with a front-mount head. Below this point the excavator wins on flexibility almost by default. Above it, on the VM-65SV, the carrier has to be configured for forestry from new anyway. Here, and only here, the two architectures cost roughly the same to put on a job and the decision turns entirely on how many hours a year the machine will mulch.

The neighbours define the boundaries. The VM-50SR draws the same 159 to 238 L/min but is rated for 25 cm material on lighter carriers. The VM-65SV takes 25 to 40 tonne machines into 50 cm timber on a much larger flow demand. This head sits between them at 40 cm on a 20 to 25 tonne carrier.

Modelling annual hours before you model the purchase

The comparison to run is not price against price, it is utilisation against utilisation. Work it as an illustration with round, obviously hypothetical numbers, then repeat it with your own.

Suppose the excavator does 1,800 hours a year of which 400 are mulching. The mulching head is an attachment on a machine that earns for the other 1,400 hours, the float is one the business already books, and the operator is already on the payroll. Now suppose the same contract pipeline offers 1,400 mulching hours a year. A dedicated carrier running a head such as the HM-90SV covers ground while travelling instead of sweeping from a stance, and on traversable country the hourly production gap is wide enough that the second machine can carry its own finance, transport and operator. Somewhere between those two cases the answer flips, and the honest way to find it is to build both rates and compare them, which is what building a tender rate and total cost of ownership are for. Excavator mulcher versus skid steer mulcher covers the production side of the same argument.

Why 130 hp on the same flow as the VM-50SR

The two heads share a flow window and differ by 50 hp of minimum carrier power, which looks odd until the pressure side is considered. Hydraulic power is flow multiplied by pressure, so identical volume at higher pressure is more power, and 40 cm material holds the rotor near relief for long stretches instead of in short bursts. The published minimum here is 130 hp (96 kW) against 80 hp on the VM-50SR, and that difference is entirely about sustained pressure. The full arithmetic sits on the VM-50SR page; the hydraulic power calculator will do it with your carrier’s measured figures.

The practical consequences are heat and pressure rather than volume. Confirm the flow the carrier dedicates under load, the pressure available at that flow, the return pressure limit and a case drain to tank, then ask specifically what the oil temperature does after an hour in heavy material. In Australian summer conditions a cooler upgrade is a common line on the order rather than an exception. See hydraulic matching and hydraulic cooling and heat. The VM range’s maximum operating pressure is published as up to approximately 410 bar, which the auxiliary relief setting must respect.

What 40 cm means for the block, not the stem

The published optimal target material diameter of 40 cm is a continuous production figure, and it takes in mature regrowth and most plantation and easement timber. The number that governs the job, though, is stems per hectare rather than the diameter of any one of them. A 40 cm stem holds roughly four times the wood of a 20 cm stem, so a well-spaced stand inside the target can be good production while a dense stand of the same diameter is slow and expensive. On dense heavy blocks, shearing and removing the stems first and mulching the residue afterwards is frequently the cheaper sequence; maximum diameter versus production diameter sets out the volume arithmetic, and Australian hardwood explains why local density makes this worse than the European figures suggest.

At 1,188 kg the head is a serious mass at reach, and on a long-boom 25 tonne machine counterweight and boom configuration belong in the purchase conversation rather than being left to the operator to discover.

Right-of-way, mine site and plantation residue

The contracts that suit it are powerline and transmission easements, mining and pipeline corridors and plantation thinning and re-establishment, all of which mix standing regrowth with material already pushed into rows. Windrowed material is the worst ground in forestry for tooling, because it hides stumps, rock and old wire under a soft surface that gives no warning. That is a carbide argument on most of this work, with blades reserved for clean green vegetation; the comparison is in blades versus carbide teeth.

Holders, not teeth, are the budget line

The surprise on this head is not tooth wear but holder damage: a tooth lost in a windrow generally takes its holder with it, and a holder is a welding job, not a spanner job. Budget tooling by the hectare rather than by the set so the real cost of heavy ground shows up in the rate, and confirm Australian stock with Machinery Specialist before signing. Wear parts to price before buying lists the items that belong in the quote, and the circuits needed by the standard hydraulic door and the grapple, tilt and heel options are documented on the VM-25SK page. Decide those options before the auxiliary kit is built, because each adds mass to the figure that must clear the chart.

The transport line in the model

Annual hours decide the architecture, but transport decides how often the answer changes. An excavator with a mulching head travels as one load that a contractor already knows how to book. A dedicated mulching carrier is a second machine with its own float, its own permits and its own idle time between jobs, and on a project with blocks scattered across a region that difference can be larger than the production gap that justified it.

The way to see it is to add a mobilisation count to the comparison rather than an hourly rate. Ten moves a year is a fleet decision; two moves a year is a production decision. Transport and mobilisation sets out what each move actually involves, and the answer often explains why a contractor with strong production numbers still runs an excavator head.

Plantation residue and windrows

Plantation and mine-site rehabilitation give this head its hardest work, and the material is unlike standing timber in ways that matter for planning. Windrowed residue is a mixture of stems, root plates, soil and whatever was pushed up with it, and its volume per metre varies wildly along the row. Production quoted per hectare on that ground is close to meaningless; the honest unit is metres of windrow per hour at an agreed residual height, measured on a sample row before the rate is set.

Root plates are the specific hazard. A plate rolled up with soil hides rock and old wire, and it presents the rotor with a face rather than a stem, so the operator works it in layers from the top rather than driving in. Where plates are dense, moving them before mulching is sometimes cheaper than reducing them where they lie, and that decision belongs in the method statement rather than to the operator on the day.

Counterweight, boom and the configuration conversation

Most attachment purchases do not touch the carrier’s configuration. This one can. On a 22 to 25 tonne machine, 1,188 kg plus bracket, hoses and options at reach is enough mass that the counterweight fitted and the boom and stick combination specified change what the operator can safely do at the radius the work needs.

The question to ask the carrier dealer is not whether the machine can lift the head, which it plainly can, but what the chart says at the radius and slew angle the job uses, over the side as well as over the front. If the machine is being bought at the same time, a shorter stick is often worth more on mulching work than the reach it gives up, because reach the operator cannot use at full mass is not reach at all. Lift chart and attachment mass explains how to read the chart properly.

Heat, fire season and the daily routine

A head working 40 cm timber generates heat in the oil and fines in the air at the same time, and during fire season that combination is the reason housekeeping is a controlled item rather than a preference. Blow down the belt housing and the carrier’s engine bay daily, check bearing temperatures by hand at each break, inspect for hydraulic weeps where a fine spray onto a hot surface is the risk, and carry the firefighting equipment the site requires. Crews should follow applicable WHS procedures, the manufacturer’s instructions and any total fire ban conditions in force; fire risk in clearing operations covers the routine in full.

Confirm before ordering

• Annual mulching hours modelled honestly, with a dedicated carrier priced as the alternative
• Carrier meets the 130 hp minimum and dedicates 159 to 238 L/min continuously at pressure
• Pressure behaviour in heavy material, not just flow: how long the circuit sits near relief
• Oil temperature after an hour in 40 cm timber, and the cooler upgrade that follows from it
• Counterweight and boom configuration for 1,188 kg plus bracket and options at working radius
• Stems per hectare on the blocks being tendered, not just their diameter
• Tooling and holder cost expressed per hectare for windrowed ground
• Australian stock and price of teeth, holders, belt and bearings, plus delivered price with bracket and hoses

Frequently asked questions