diff --git a/code/modules/heavy_vehicle/mech_interaction.dm b/code/modules/heavy_vehicle/mech_interaction.dm
index 56fd2afeb7e..8221afbd7be 100644
--- a/code/modules/heavy_vehicle/mech_interaction.dm
+++ b/code/modules/heavy_vehicle/mech_interaction.dm
@@ -318,9 +318,10 @@
 
 /mob/living/heavy_vehicle/Move()
 	if(..() && !istype(loc, /turf/space))
-		if(legs && legs.mech_step_sound)
-			playsound(src.loc,legs.mech_step_sound,40,1)
-		use_cell_power(legs.power_use * CELLRATE)
+		if(legs)
+			if(legs.mech_step_sound)
+				playsound(src.loc, legs.mech_step_sound, 40, TRUE)
+			use_cell_power(legs.power_use * CELLRATE)
 	update_icon()
 
 /mob/living/heavy_vehicle/Post_Incorpmove()
diff --git a/code/modules/mining/machine_processing.dm b/code/modules/mining/machine_processing.dm
index fa2d163083c..0f47e09daba 100644
--- a/code/modules/mining/machine_processing.dm
+++ b/code/modules/mining/machine_processing.dm
@@ -1,3 +1,9 @@
+//Modes the smelter can work with, bitflags
+#define SMELTER_MODE_IDLE BITFLAG(0)
+#define SMELTER_MODE_ALLOYING BITFLAG(1)
+#define SMELTER_MODE_COMPRESSING BITFLAG(2)
+#define SMELTER_MODE_SMELTING BITFLAG(3)
+
 /obj/machinery/mineral
 	var/id //used for linking machines to consoles
 
@@ -117,14 +123,14 @@
 		if(!O)
 			continue
 		var/processing_type = ""
-		switch(machine.ores_processing[ore])
-			if(0)
+		switch(machine.ores_processing[ore]) //Yes we could use bitflags, but I don't care enough about it here
+			if(SMELTER_MODE_IDLE)
 				processing_type = "Idle"
-			if(1)
+			if(SMELTER_MODE_SMELTING)
 				processing_type = "Smelt"
-			if(2)
+			if(SMELTER_MODE_COMPRESSING)
 				processing_type = "Compress"
-			if(3)
+			if(SMELTER_MODE_ALLOYING)
 				processing_type = "Alloy"
 		ore_list += list(list("name" = capitalize_first_letters(O.display_name), "processing" = processing_type, "stored" = machine.ores_stored[ore], "ore" = ore))
 	data["oreList"] = ore_list
@@ -158,13 +164,13 @@
 
 		switch(choice)
 			if("Nothing")
-				choice = 0
+				choice = SMELTER_MODE_IDLE
 			if("Smelting")
-				choice = 1
+				choice = SMELTER_MODE_SMELTING
 			if("Compressing")
-				choice = 2
+				choice = SMELTER_MODE_COMPRESSING
 			if("Alloying")
-				choice = 3
+				choice = SMELTER_MODE_ALLOYING
 
 		machine.ores_processing[ore_name] = choice
 		return TRUE
@@ -278,6 +284,10 @@
 
 /**********************Mineral processing unit**************************/
 
+/**
+ * A list containing alloy data, initialized only once by the first `/obj/machinery/mineral/processing_unit` that initializes
+ */
+GLOBAL_LIST_EMPTY_TYPED(alloy_data, /datum/alloy)
 
 /obj/machinery/mineral/processing_unit
 	name = "industrial smelter" //This isn't actually a goddamn furnace, we're in space and it's processing platinum and flammable phoron... //lol fuk u bay it is //i'm gay // based and redpilled
@@ -296,9 +306,24 @@
 	///How many sheets in a second this smelter can make (more or less, rounded up depending on ticklag)
 	var/sheets_per_second = 50
 
+	/**
+	 * An associative list
+	 *
+	 * Key is a string, representing the ore name (eg. uranium, diamond, gold)
+	 *
+	 * Value is a bitflag, representing the operation mode for said ore, see `SMELTER_MODE_*` defines
+	 */
 	var/list/ores_processing[0]
+
+	/**
+	 * An associative list
+	 *
+	 * Key is a string, representing the ore name (eg. uranium, diamond, gold)
+	 *
+	 * Value is a number, representing how many ores are stored in the device for said ore type
+	 */
 	var/list/ores_stored[0]
-	var/static/list/alloy_data
+
 	var/active = 0
 	idle_power_usage = 15
 	active_power_usage = 150
@@ -314,14 +339,13 @@
 /obj/machinery/mineral/processing_unit/Initialize()
 	. = ..()
 
-	// initialize static alloy_data list
-	if(!alloy_data)
-		alloy_data = list()
+	// initialize static alloy_data list, if it's not already initialized
+	if(!length(GLOB.alloy_data))
 		for(var/alloytype in subtypesof(/datum/alloy))
-			alloy_data += new alloytype()
+			GLOB.alloy_data += new alloytype()
 
 	for(var/O in GLOB.ore_data)
-		ores_processing[O] = 0
+		ores_processing[O] = SMELTER_MODE_IDLE
 		ores_stored[O] = 0
 
 	return INITIALIZE_HINT_LATELOAD
@@ -361,6 +385,8 @@
 	RegisterSignal(console, COMSIG_QDELETING, PROC_REF(handle_console_deletion))
 
 /obj/machinery/mineral/processing_unit/proc/handle_console_deletion()
+	SIGNAL_HANDLER
+
 	console = null
 
 /obj/machinery/mineral/processing_unit/attackby(obj/item/attacking_item, mob/user)
@@ -408,13 +434,14 @@
 		if(sheets >= ROUND_UP(sheets_per_second*seconds_per_tick))
 			break
 
-		if(ores_stored[metal] > 0 && ores_processing[metal] != 0)
+		if(ores_stored[metal] > 0 && ores_processing[metal] != SMELTER_MODE_IDLE)
 			var/ore/O = GLOB.ore_data[metal]
 			if(!O)
 				continue
 
-			if(ores_processing[metal] == 3 && O.alloy) //Alloying.
-				for(var/datum/alloy/A in alloy_data)
+			//Alloying materials
+			if(ores_processing[metal] & SMELTER_MODE_ALLOYING && O.alloy)
+				for(var/datum/alloy/A in GLOB.alloy_data)
 					if(A.metaltag in tick_alloys)
 						continue
 
@@ -427,7 +454,7 @@
 
 						for(var/needs_metal in A.requires)
 							//Check if we're alloying the needed metal and have it stored.
-							if(ores_processing[needs_metal] != 3 || ores_stored[needs_metal] < A.requires[needs_metal])
+							if(!(ores_processing[needs_metal] & SMELTER_MODE_ALLOYING) || ores_stored[needs_metal] < A.requires[needs_metal])
 								enough_metal = FALSE
 								break
 
@@ -450,7 +477,8 @@
 								console.alloy_mats[A] = console.alloy_mats[A] + 1
 							new A.product(output)
 
-			else if(ores_processing[metal] == 2 && O.compresses_to) //Compressing.
+			//Compressing materials
+			else if(ores_processing[metal] & SMELTER_MODE_COMPRESSING && O.compresses_to)
 				var/can_make = Clamp(ores_stored[metal], 0, ROUND_UP(sheets_per_second*seconds_per_tick) - sheets)
 				if(can_make % 2 > 0)
 					can_make--
@@ -460,7 +488,7 @@
 				if(!istype(M) || !can_make || ores_stored[metal] < 1)
 					continue
 
-				for(var/_ in 1 to (can_make*2))
+				for(var/_ in 1 to (can_make/2))
 					if(console)
 						console.points += O.worth * 2
 					use_power_oneoff(300)
@@ -469,7 +497,8 @@
 					console.output_mats[M] += 1
 					new M.stack_type(output)
 
-			else if(ores_processing[metal] == 1 && O.smelts_to) //Smelting.
+			//Smelting materials
+			else if(ores_processing[metal] & SMELTER_MODE_SMELTING && O.smelts_to)
 				var/can_make = Clamp(ores_stored[metal], 0, ROUND_UP(sheets_per_second*seconds_per_tick) - sheets)
 
 				var/material/M = SSmaterials.get_material_by_name(O.smelts_to)
@@ -514,3 +543,8 @@
 			laser_rating += P.rating
 
 	sheets_per_second += scan_rating + cap_rating + laser_rating
+
+#undef SMELTER_MODE_IDLE
+#undef SMELTER_MODE_ALLOYING
+#undef SMELTER_MODE_COMPRESSING
+#undef SMELTER_MODE_SMELTING
diff --git a/html/changelogs/fluffyghost-fixmachineprocessing.yml b/html/changelogs/fluffyghost-fixmachineprocessing.yml
new file mode 100644
index 00000000000..dde351a524d
--- /dev/null
+++ b/html/changelogs/fluffyghost-fixmachineprocessing.yml
@@ -0,0 +1,43 @@
+################################
+# Example Changelog File
+#
+# Note: This file, and files beginning with ".", and files that don't end in ".yml" will not be read. If you change this file, you will look really dumb.
+#
+# Your changelog will be merged with a master changelog. (New stuff added only, and only on the date entry for the day it was merged.)
+# When it is, any changes listed below will disappear.
+#
+# Valid Prefixes:
+#   bugfix
+#   wip (For works in progress)
+#   tweak
+#   soundadd
+#   sounddel
+#   rscadd (general adding of nice things)
+#   rscdel (general deleting of nice things)
+#   imageadd
+#   imagedel
+#   maptweak
+#   spellcheck (typo fixes)
+#   experiment
+#   balance
+#   admin
+#   backend
+#   security
+#   refactor
+#################################
+
+# Your name.
+author: FluffyGhost
+
+# Optional: Remove this file after generating master changelog.  Useful for PR changelogs that won't get used again.
+delete-after: True
+
+# Any changes you've made.  See valid prefix list above.
+# INDENT WITH TWO SPACES.  NOT TABS.  SPACES.
+# SCREW THIS UP AND IT WON'T WORK.
+# Also, all entries are changed into a single [] after a master changelog generation. Just remove the brackets when you add new entries.
+# Please surround your changes in  double quotes ("), as certain characters otherwise screws up compiling. The quotes will not show up in the changelog.
+changes:
+  - bugfix: "Fixed a runtime found on mechs."
+  - bugfix: "Fixed machine processing for ores going in the negatives for alloying."
+  - backend: "Some more optimizations, DMdocs, turned a var into a global one, some defines added and made into bitflags, yada yada you know the usual deal."